Beginner glossary Q&A: complication, caliber, jewel count, power reserve · RWI-30062

A complication is any function beyond hours, minutes and seconds. A date window counts, technically, and so do a chronograph, GMT hand or moon phase. More complications usually mean more parts, more thickness and more service cost. For a first everyday watch, decide which functions you'd really use before treating them as value.

Caliber is the movement's model designation, like a part number. Two watches from different brands can share the same caliber family with different finishing or regulation. On a spec sheet it tells you what's inside and roughly what service parts are available. It doesn't tell you how well that particular example was adjusted.

Jewel count describes bearings used in a movement design; it is not a quality ranking. Compare the documented movement architecture and service support rather than assuming a higher count makes one watch better.

Power reserve is how long the watch runs from full wind until it stops. It matters if you rotate watches: a 38-hour reserve may stop over a weekend off the wrist, while 70-plus hours may not. One clarifying point is that rate stability often gets worse near the end of the reserve, so the full figure is not all precision-grade running time.