A quartz watch uses the battery as the energy source. Every second the circuit generates a pulse to the motor that drives the second hand to move forward. The electronic pulse is so reliable that ensures a quartz watch to have 5-15 seconds discrepancy in one month. A quartz watch is much lower in price than its mechanical counterpart because it is mass-produced in an automated production line. Quartz movement can be easily made very thin and small.
In comparison, mechanical movements are much craftier, rendering a more dynamic appearance. Mechanical watches are more expensive because more specially-made parts are needed; more labor is required in assembly and adjustment, creative design, artistic carving and polishing.
A mechanical watchs accuracy is affected by many factors like temperature, position, motion, parts condition, etc. 10-30 seconds discrepancy a day is normal. The most accurate mechanicals can have at least 3-5 second discrepancy per day.
If one component in a quartz watchs circuit board is out of order, the entire integrated circuit has to be scraped as it is impossible to repair a single electronic component, unless the entire circuit board is changed. A mechanical watch, by theory can last as long as there are spare parts. Many vintage watches of centuries old are still running strong.
Despite the low cost and super accuracy, quartz watches do not have personalities. I feel all quartz watches are very much alike regardless of makes, prices, functions, design. On the other hand, every mechanical watch is different even within the same brand the same model.
Electronic pulses in quartz are invisible and abstract. Mechanical parts are tangible and concrete in front of your eyes. These solid parts are in presence here to record and witness the lapse of your time.
Modern technology has not made wristwatch to disappear. If someone says it is not necessary to wear a watch as a cell phone tells the time, he or she must be a dull and cold-hearted person. Nowadays a watch is more than just a horological device, but has become more of fashion jewelry. Like a business card, the watch you are wearing tells a lot about you, your characteristics and individualism.
Mechanical watches are essentially hobbies or collective items for the people who can afford. The timing functions of space shuttle and modern Olympic Games are all performed electronically.