Use the chrono very often. The Polar HRM for my runs & tennis. Great amount of information in terms of laps, distance, cals, weekly volumes etc. Well beyond the capabilities of a conventional watch.
In the gym I often use the diver timing bezel to time the whole session as the 30min chrono is not long enough. Infrequently, I use the chrono during swims to time the laps, & also use the bezel to check the total duration of the swim. Use the Tag F1 for these activities
Use my regular mechanical Longines chrono daily to time my attempt at Sudoku. Few days back I used it for a more depressing reason, to time the apnoea (no breathing) duration for a set of brain death tests. Problem on the mechanical watch is that if one forget to put it off, one runs out of reserve quickly & have twice realized this only after the watch stopped.
fnk