I could raise fees by about 8.US dollars My current fees are about 32.Us/h.
A 25% hike may give some students pause - rather steeper than just a cost of living type increase. You may wind up losing more than you make.
When/how to do it is totally at your discretion.If you have 25 years teaching experience, a Ph.D. and two grand pianos in your studio and teach very advanced students then you should be charging at the higher end of the price range. A Merecedes Benz is going to cost more than a Volkswagen just as a Bosendorfer or Steinway will cost a lot more than "lesser quality pianos". So Why should I be any different?