Birthdays used to be a thing at one workplace I went to. And I have to admit, I was on such low wages at that time, I objected to being told how much to contribute to the collective pot, when I was going without a lot of stuff myself because I couldn't afford anything, basically. But yes, for those who like 'whip rounds' birthdays were a thing. Better when you can contribute what you want/can afford really though, and optional.