In my country, you get usually I think 4 or 5 weeks of vacation, when you're 50 you get a week more, at 60 still another week more. This applies to all jobs.

I like it this way. My T is usually more or less consistent with it, two weeks over Christmas, two weeks in Summer, one week in between. I think he needes time off and should take it as well, but more than two weeks in a row is too much for me. He did a 2.5 week vacation last year and I freaked out enough to need two sessions a week for months after.

So overall, I think there should be a maximum per year, which should be more or less sensible, 5 or 6 weeks seems fine to me. And that time should if possible be split up a bit so clients don't have to go long time without contact. But I also do think that during that time the T should really take time off, not check emails every day, do phone calls and so on. Otherwise it's not time off.