Rotating a collection means spreading your wear across it on purpose. It keeps every automatic running from time to time, shows you which pieces you really love, and makes it easier to decide what to sell or buy next.
Measuring rotation
Horology's rotation score sums up how evenly your wrist time is spread, from 0 to 100. 100 means every watch is worn equally; 0 means one watch gets all of it. Technically it is the normalized entropy of your wears: the same measure of evenness ecologists use for how species share a habitat.
| Wears per watch | Rotation score |
|---|---|
| 10, 10, 10 and 10 | 100 |
| 12, 10 and 8 | 99 |
| 20, 5 and 5 | 79 |
| 25, 10, 4 and 1 | 69 |
| 17, 1, 1 and 1 | 42 |
| 30 on one of four watches | 0 |
Watches you've set aside on purpose, marked out of rotation, aren't counted, so a piece kept for special occasions doesn't drag the score down.
Ways to wear more of your collection
- Decide which watches are in rotation, and set the rest aside on purpose.
- Give watches a rhythm: a dress watch for the office on Fridays, a diver at the weekend.
- Let chance decide. Horology's Pick for me favors the watches that have waited longest since you last wore them, with a little randomness, and leans slightly toward your favorites.
- Look back at the month. A wear calendar shows at a glance which watches you reach for, and on which days.
Rotation and cost per wear go together: the watches you rarely wear are usually the ones that have cost the most per wear.