If you do something once, it’s hard to say whether you actually like it or not. (It will probably be different from what you already do, so it’ll either be immediately fun, or weird and different and therefore not fun. Either way, it’s a bad indicator of whether you’ll enjoy it if you keep doing it. Playing bocce ball once is fun, but I don’t think I’d want to join a bocce league. Learning languages for 1/2 hour once is not fun, but sticking with it has been pretty fun.)

If you do it every day for a year, you definitely know whether you like it or not.

Where’s the border? I feel like it’s something along the lines of “once a week for 2 months”, although maybe that’s just because a lot of things tend to happen along that timeline.