Older coworker here (Xennial). I’ve always used all of my sick days. One job had a week you could carry over to the next year. I held that week if I didn’t need it because next year I’d be making more money. Next job started with sick bank but stripped it away and lumped everything into one PTO bucket that they weren’t legally bound to offer carryover from. Oddly enough, they started having trouble with attendance in November and December as people just took days off whenever. Oh well.