A lot of my custies move every couple of years (Army houses) so the way I do it is as I get new custies, I put the price rise onto them. So if a house is €15 and the custy moves away, the new tenant gets the new price of €16. It filters through over time.
The thing to remember is, with inflation, after 3 or 4 years, you're doing the job today for at least 8% to 10% less than you did when you started. Imagine if a firm you worked for paid you 8% less after a couple of years. !!

If you lose a few from every hundred custies you'll be cleaning less for the same money, so that will free you up to get more custies at the new prices. Takes guts to increase prices, but some find it easier than others.
Doesn't matter much at the moment for me, if I didn't have winter customers for snow clearing, I'd have nothing to do since mid January.

HTH