Hi,if you are still doing fine,after ten years,then you have already been making,mostly the right decisions
You should approach the question asked,from the other end...
if you are continuing to deal with these small customers - then you are happy,with the arrangement.
There has to be a reciprocal link. They could be good PR,friends,family...or just be in a good spot,for a sign-written van
Remember,we are dealing with that most peculiar,unpredictable entity - the human. Some of those long-term customers,may wonder why you have not increased prices,and not worry. Some will spit the dummy out. There are those that may have other "issues" going on,and resist change,by telling everyone,you upped things because your're struggling/drinking/gambling....
My point is,you can please some of the people,some of the time....
My personal aim,if any of these customers are in contact with each other,would be to keep things the same with some,and up the charges to the lesser minions .... they will be so involved,trying to work out the reasons,you will bypass the bulk of the flak
....Hang on,that sounds like the phone.....I'm wanted in Brussels....