How a quartz watch works
A battery sends a small current through a tiny quartz crystal, which vibrates at a very steady 32,768 times a second. A circuit counts those vibrations and steps the hands (or updates a digital display) once a second. There is almost nothing to wear out. A quartz watch typically keeps time to within 15 seconds a month, the battery lasts two to four years, and the watch costs less to make. Solar-charged quartz watches replace the battery with a rechargeable cell under the dial and run for decades on light.
How an automatic works
An automatic is a mechanical watch: a coiled mainspring stores energy, a train of gears lets it out, and a balance wheel swinging back and forth five to eight times a second meters the release. "Automatic" means a weighted rotor inside winds the mainspring as your wrist moves, so you do not wind it by hand (though you can). A good automatic keeps time to within 10 to 20 seconds a day, runs for about 40 hours off the wrist, and wants a service every five to seven years. What you get for that is a living mechanism: a sweeping seconds hand, no battery ever, and a watch that can be kept running for generations.
Which one for a first watch?
If you want a watch that is always right and asks nothing, quartz. If you want a watch as an object, with a mechanism you can hear and feel and keep for life, automatic. Many people end up with one of each: a quartz for the week and an automatic for the weekend. Neither is the "better" answer; the wrong answer is an automatic bought by someone who will be annoyed the first time it is two minutes slow.
Size and strap
Case diameter is the number everyone quotes, but lug-to-lug (the length from strap end to strap end) decides whether a watch fits your wrist. A 36 to 40 mm case suits most wrists; 41 to 44 mm reads as a sports watch and needs a wider wrist to sit flat. Look at the thickness too: under 12 mm slips under a cuff. Straps come in widths from 18 to 22 mm; a metal bracelet is durable and heavier, leather is lighter and dressier, a NATO or rubber strap is for water and summer. Most straps can be swapped at home with a spring-bar tool.
Water resistance, in plain terms
The rating on the dial is a laboratory pressure test, not a promise about diving. Read it like this:
| Marking | Fine for | Not for |
|---|---|---|
| 3 bar / 30 m | Rain, hand washing, splashes | Swimming, showers |
| 5 bar / 50 m | Showering, brief swimming | Diving, water sports |
| 10 bar / 100 m | Swimming, snorkelling | Scuba diving |
| 20 bar / 200 m | Diving | Saturation diving |
Whatever the rating, never pull the crown or press the buttons under water, rinse salt water off, and have the seals checked when the battery is changed or every few years; rubber gaskets age even if the watch is never wet.
Buying it
New watches at DiOro999.9 come with box and papers and the maker's warranty, and each listing states the movement type, the case size and the water rating. If you are between two, ask on WhatsApp and say what your wrist measures and what you will do with it; that answers most of the question.