Class prices are increased according to many factors. When classes do go up, we give the members at least 30 days notice of the increase and include a statement as to why. Things like increased overhead, instructor pay raises, etc.
My personal training clients are on an entirely different rate system. When my rates go up, my long term clients are one rate hike behind. That is, if my new client rate was at $60 dollars and the new rate is going to $65, my long term clients were probably at $55 and now go to $60. My long term clients always are at a lower rate. It is part appreciation and part client retention.