How common all depends on how many private schools you have and how good they
are and the type of schedule an art teacher has. My old school had a big
turnover in art teachers because the schedule was crazy and they only offered
part time ( more like full time at part time wages)....I ended up working 6
years...the longest in their history and my kids got a really good
education...(although they have in public school later on too). I still keep
contact with the school 10 years later and have several good friends there.
So....it just depends...
Laurie