My last company was pretty easy with regards to letting me have time off.
It was a simple case of if I had no holiday entitlement left, I didn't get paid.
Can't seem to do that in my current job, it's 20 something days and that's it.
Also not allowed to take time off in school holiday periods.
That bit suits me as I don't have kids and I don't like paying inflated premiums anyway.
Both bosses and other staff have family / kids so fairer if I don't anyway.
I also try to take my holidays over Christmas as this is when we are quietest.
Couldn't believe the first time I tried to take an extra few days for something when I had no entitlement left. It was like the biggest dilemma ever.
The only difference was they didn't have to pay me, which I thought would have worked in their favour.
It wasn't like there was no one else to run the ship, everyone in the workshop can do the same jobs.
Another issue is not being allowed to roll over unused days

AND if I don't take them, then I don't get paid them.
But that doesn't work out too bad with taking time off at Christmas as one week is in one year, the second week I am off anyway (Christmas week) and the third week is New year

WIN WIN