When I was younger and working more junior roles and moving from role to role every year or 2 (generally headhunted) there was a use it or loose it mentality. You wouldn’t take the day off the moment you had a sniffle / didn’t feel 100%.

However once your older, have kids and are at the role for more then a few years, that sick leave is often “banked” for when the kids come down with whatever is going around the schoolyard this week