When I give a quote to a new customer I submit a price I'm happy to do the work for regardless of how cheap or expensive the previous window cleaner was before me.
I'm happy picking up 1 in every 2 or 3 quotes I give because that's the ratio I gain according to my prices.
I'm not interested whether I'm undercutting or overcharging. I just want to be happy to earn what I feel I can achieve.
Who doesn't want to earn more today than they did last year, it's only natural. If you lose some customers to some other window cleaner, all it means is that they haven't reached the stage where you are at in relation to pricing, it's life, live with it and move on.