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Time is divided naturally by striking astronomical phenomena such as the periodical renewal of the seasons, the phases of the moon, or the regular succession of day and night.
To divide time into smaller fractions, artificial means are needed, such as sun dials which mark the movement of the shadow cast by the sun; or clepsydras which use a controlled flow of water. Since 1657, the oscillatory movements of a mechanical movement have been used to divide time.

The electronic age did not pass watches by. In the late 1960s, a Swiss research group designed and tested the first electronic watch movement, which later became known as the quartz movement. These battery-powered watches also permitted a deviation from the centuries-old analog display with the introduction of digital display.

Quartz watches are extremely accurate thanks to their high frequency of vibrations (32 kHz). Their daily variation is equivalent to much less than a second per day.

Comparatively speaking, the frequencies of oscillations (number of one-way movements of the regulating organ per hour) mainly used in mechanical watches range from 21,600 Ah (3 Hz) to 28,800 Ah (4Hz), allowing a variation of less than 10 seconds a day.

Water resistance is measured in bars (unit of pression, 1 bar being equivalent to 1 atmosphere), and watches are tested at these pressures for certain period of time. Exceptional pressure, as when diving, may exceed those limits, so if you are a keen diver you will need a watch that can tolerate that pounding.
Translation varies and your best guide is your supplier as it will almost certainly be part of the guaranteee.

Manufacturers often measure water resistance to a number of feet (ft), meters (m) or atmospheres (atm). Watches marked "water resistant" with or without additional indication of high pressure must comply with NIHS 92-10 watch Standard (corresponding to ISO 2281 international Standard). Such watches are designed for everyday life and must be water resistant during exercices such as short swimmings. They can be worn in different temperature and pressure conditions but are under no circumstances designed for scuba diving.

Divers' watches must be water resistant at 330 ft minimum. They must also feature a time controller and comply with standards provided by NIHS 92-11 (ISO 6425) : luminosity, shock resistance, anti-magnetism, band solidity.

Remember that if you are going to be moutain climbing, parachuting, sky diving, hang gliding, or skiing, it is advisable to use a watch that is atm damage-protected as pressures change both above and below sea level.

For regular water use, solid metal cases or specially constructed products are recommended, including screwed-in case backs and crowns.
Do not hesitate to ask your next dealer about water resistance functions, and remember that only professional changing battery will guarantee the seals and thus the water resistance of your timepiece.

Mechanical and automatic watches should be cleaned and serviced every three years to ensure trouble-free time keeping. The moving parts of quartz watches also need maintenance, as they are not under tension and any small, foreign particle is sufficient stop them.

Where fitted, the battery needs to be changed when drained. This is the time for routine maintenance. Apart from changing the battery, digital quartz watch need no routine maintenance. Where water resistant seals are fitted, cleaning is required less often, however seals must be changed whenever the case back is removed. Otherwise they should be changed annually and resistancy checked using pressure equipement, through the manufacturers' agent.

It is worthwhile remembering that regular exposure to chemicals, or sea water, can damage straps, plated cases and bracelets and a solid metal or specially constructed material is recommended if regularly used in these conditions. Cosmetics and perfumes can also cause damage if directly applied to plated dials and straps.

A Chronograph is a timepiece equipped with additional time measurement functions independent of normal time-telling.

A Chronometer is a high-precision timepiece which movement, after rigorous testing, has received an official timing certificate from and official timing bureau.

Watches providing additional measurement functions to the hours, minutes and seconds are referred to as "Complications". The best-known complication watches are calendar watch, the most common of which display only the date. There are also chronographs with a center seconds hand which can be started, stopped and brought back to zero using one or two push-button on the side of the watch. Other additional functions include second time zone, alarm, moonphase, repeater, perpetual calendar, etc.

Usually between two and five years, depending on the type of the watch, its dimensions and the quantity of energy requested by the different functions. For instance, a chronograph will have a higher energy consumption than a watch indicating the hours and the minutes only.

Certain types of watches feature a power reserve indicator : when the seconds hand starts jumping every five seconds, it is time to have the battery replaced by a qualified watchmaker.Special lithium-iodine batteries reach a theoretical lifetime of ten years.

Often the bezel (top ring on the case), serves to record additional data, and can often move in both directions to provide a number of functions. A unidirectional bezel only turns one way to prevent any danger of false manoeuvre. Especially important when being used to measure diving times as even if the bezel is knocked and moved it will simply indicate the diver has less air or decompression time rather than more.

In order for timepieces to be read in the dark, a luminescent material is laid on the dial indexes and hands. Generally speaking, the emission of light is either of photoluminescent type (determined by a exciting luminous radiation) or of radioluminescent type (determined by the radioactivity of the material).

Timepieces featuring radioluminescent emission are mostly designed for very specific uses : military watches, professional divers watches, etc. In this case, the use of radioactive material is strictly defined by ISO 3157 Standard which allows only two types of radionucleides : tritium (3H) and promethium (147 Pm). It is important to specify that these radionucleides emit a radiation of low energy.

ISO 3157 Standard allows an optional marking for timepieces emitting less than a certain value. The marking may be made on the dial as follows :

deposits activated by tritium : T

deposits activated by promethium : Pm

On the other hand, timepieces with a higher value, such as divers' watches, must be marked as follows :

deposits activated by tritium : T 25

deposits activated by promethium : Pm 0,5

The indication "T Swiss made T" means that the watch is Swiss and contains a certain quantity of tritium that emits less than 227 MBq (7,5 mCi).The indication "Swiss T<25" means that the watch is Swiss and contains a certain quantity of tritium that emits less than 925 MBq (25 mCi).

Most of the Swiss watches use a light emission of photoluminescent type. Some of them bear the optional marking "L Swiss Made L" to indicate it.

The jewels are synthetic sapphires or rubies which have been drilled, champfered and polished to serve as bearings for gears in watches, reducing friction or mechanical parts to a bare minimum.

Generally speaking, one may say that a simple mechanical watch (hours, minutes and seconds hands) should include at least fifteen jewels located in the places most subject to wear due to friction. It should be fitted with a shock-absorbing system on the balance, a good quality balance-spring and an unbreakable spring.

While counterfeiting has always existed, it has become a dominant feature of our day and age. Much more than in the past, the value of products depends on their intellectual content (brand image, design, technical innovation, etc.). This is much easier to steal than material objects and often more attractive for criminals. Watches are a popular target of this modern form of criminality.

Counterfeiters usually focus on the appearance rather than the technical parts of a watch as this results in much easier profits. Counterfeit watches generally incorporate a whole range of illegalities: the illicit reproduction of a brand, a spurious country-of-origin mark, the copy of a design, and often falsified hallmarks or a bogus classification ("chronometer", for example).

Tourists are the counterfeiters' favourite targets. Counterfeit networks also make considerable use of non-direct sales methods (newspapers, television and now the Internet). As often as they can, sellers try to pass off their counterfeit goods as the genuine article in order to procure the highest price possible. If they are dealing with someone who is not taken in by their sales pitch, they lower the figure.

Consumers who knowingly purchase a counterfeit product are often motivated by curiosity, snobbishness, or simply the belief that they have made a good bargain. In reality, they are always the loser and risk exposing themselves to a number of disappointments and inconveniences:

• they will find they have paid too much for a worthless product;
• they have no guarantee or after-sales service;
• they are risking their health as counterfeit products do not adhere to quality norms such as protection against allergies, radioactivity, etc;
• they might well be questioned by customs authorities upon entering another country; their watch could be seized and they could easily be slapped with a fine.

Purchasing counterfeit goods contributes to the operation of a whole clandestine economy, one which resorts to such repugnant methods as the exploitation of child labour, and which ruins legitimate companies, thereby creating unemployment.

To protect consumers and preserve a healthy industry, we have to conduct a relentless battle against the counterfeiters and their accomplices. It is a struggle spearheaded by the efforts of the specialized services of watch companies directly concerned and the departments of the FH. On their side, authorities have come to recognize that counterfeiting is one of the major scourges, against which a powerful arsenal has to be deployed. Strict laws are coming into force everywhere while customs authorities are stepping up surveillance.

Advices

• Only buy a brand watch at one of the brand's authorized retailers and never be tempted by a "good bargain" offered on a street corner, a beach, in a disreputable shop or in leaflets holding out the promise of something exceptional.
• Never forget that modern means of communication (television, the Internet) must be used with discernment. Yielding to a tempting offer from a dubious source is asking for trouble.
• And, of course, never purchase a counterfeit watch knowingly or willingly. This is both risky and irresponsible.

A good watch is first of all one which is appealing.

Generally, mechanical watches, by nature of their movements, are more costly than quartz watches. Beyond this, there are a number of factors that affect the cost of watches.

In relation to the movement, one may say that even on cheap models, this part is well designed and that all the highly functional elements make use of the latest technologies discoveries; economies are made on the non-functional parts. In very carefully made movements, all parts, whether functional or not, are finished with great care. All steel components are polished; bridges are decorated and chamfered; all parts are of the highest quality and undergo stringent tests; in short, the manufacturing standards are extremely high.

Case materials vary. There are plastic, resins, stainless steel, base metal (usually brass), gold-plated base metals, gold-filled and precious metals. Check either the back of the watch case, or the documents accompanying the watch for the disclosure of metallic content.Plastic and resin composites generally are the least costly and are found primarily in fashion and sport watches. Stainless steel is not a precious metal and is widely used in sport watches.

Prices of gold-plated watches vary depending upon the karatage of the gold (e.g. 14 kt or 18 kt) and the thickness of the plating - measured in microns. Gold plating can range from 2-micron thickness to 30 microns and more. Precious metals used on watch cases include varying karat golds, sterling silver and, in some very high-end watches, platinum.

Crystal types also vary, but with fewer options. Generally, the crystal, which is the glass-like covering designed to protect the dial of the watch, is either plastic, mineral glass, or synthetic sapphire. Plastic is mostly used in lower-priced, mass-market watches. Mineral glass is more common and sturdier. Sapphire crystals, more expensive than mineral glass, are not only sturdy, but also highly scratch-resistant.

Bracelets can also influence watch prices considerably. Aside from plastic and rubber strap, leather and metal straps can dramatically affect the cost of the watch. Leather straps can range from $10 to $ 100 for specially treated or exotic (though not endangered) skins. Similarly, metal bracelets can range from inexpensive base metals to precious metals, to specially developed tungsten carbide or titanium.

Today, the highly competitive market is such that the quality of watches is inexorably pushed upward, a trend which translates into a range of products constantly improved in order better to meet consumers' need and expectations.

Style, design and watch brands are purely individual tastes. In any case, fine watches should be purchased at reputable jewelers or other authorized retailers who have a knowledgeable staff and strong after-sales services.

Look for the manufacturer's warranty to ensure authenticity, as well as original packaging, boxing and informational materials.

Most fine watch manufacturers have strategically located services centers for watch maintenance and repair.