@sun In that case they can limit the maximum amount to 29 days or something. Why insist that employees used up their vacation time instead of letting it expire?

This actually going much further than the nag email. A while back they created a "Christmas Shutdown", when everyone goes on vacation. I was wondering, what if I use up all my vacation before Christmas and then have no days, am I fired? But even that was not enough. Some 5 years ago they added "quarterly recharge days", which also take it out of your PTO.