Very good post. I think a lot of small to medium sized companies are afraid to do this out of some irrational fear that they're going to anger their customers. Yeah a few WILL be truly angry and they WILL drop you. These are probably the real PITA customers who would still find something to complain about even if you serviced them for free, so no big loss on your end. They're actually doing you a favor so look at it that way. You probably hate servicing them but now you don't have to be the bad guy when the relationship ends.
Some will be angry but they'll accept it and they'll continue to use you. 95 percent won't even notice a minimal price increase at all and if they do, they won't say a word because they understand that's just how the world works. A gradual 1% to 4% increase every year or two isn't an issue for most customers. If you double or triple the price overnight, then you're going to have some problems.
Arby's doesn't need to explain to you why their "5 for $5" deal from 15-20 years ago is now called the "5 for $9.95". As an intelligent business owner, you can probably figure it out on your own. Their food costs went up, taxes went up, and minimum wage isn't $4.50 an hour anymore. They're not going to sell roast beef sandwiches at a loss, they're going to pass their increased costs of doing business onto you, the hungry customer who willingly chose to walk into their store. As a customer, you can either cry about it and threaten to go eat somewhere else (Arby's won't care), or you can just accept reality and fork over $10.
If you're doing $100,000 in gross sales and implement an across the board 3% price increase every year or two, you just gave yourself an instant $3,000 pay raise. How much blood, sweat, and tears would you have had to put into your business in order to obtain $3,000 worth of new accounts/customers? If a few cheap storefront owners drop you because of it, you're still going to end up just fine so it's nothing to lose sleep over.