The problem only becomes apparent when you do need to adjust the price, as you've accustomed the customers to said price for ten years.
I had this problem a while back, as I had sections of rounds which had the same price for X yrs, ut combined with all the other higher/newer prices the days rates were still good. However when the time came to increase the prices, they didn't like a £2 - £5 pound increase and I lost the odd customers. Yet no doubt, like yourself and others, I'd doesn't matter too much as I already had replaced/gained new work to compensate this, so it ends up a win/win anyway