Raise prices in small increments; they are easier to swallow and will generally be ignored. Do not wait to pass thru small increases. When you wait, customers do not notice and then will not remember you went three or four years without a price increase. They will never call and ask why you did not raise prices. A good excuse is to do it when the rest of the market is doing it. You will not stand out. Do it when material prices are advertised as going up on the television. Do it gently but frequently. Do it and do not wait.