A dead quartz watch is not always just a battery
Battery voltage and condition are the obvious first checks. If a suitable fresh cell does not restore normal operation, replacing batteries repeatedly wastes time and can obscure the real problem.
Movement replacement can be the better option
For common quartz movements, a complete movement replacement can be more reliable and economical than component-level electronic repair. The dial, hand height, stem, calendar and case fit all have to match.
Battery leakage can be destructive
An old leaking cell can corrode contacts and movement components. A watch that has sat dead for years deserves inspection rather than a battery forced into a contaminated movement.
Hands can stop a healthy movement
A bent hand, loose marker or poor clearance can physically block the gear train. Symptoms sometimes appear electrical even when the problem is mechanical.