When was the last time you raised your prices? If you are a union contractor, you probably raise them (in some fashion) every year when the contract renews and the labor costs go higher. There are some years when you raise the labor rate. There are other years when you raise the "other stuff," i.e., parts multipliers, trip charges, truck materials charges, etc. and not raise the labor rate.
Those of you who are not union contractors may not have looked at your costs (both direct and overhead) in a while to see if a price increase is justified. If you are on flat rate, the costs can get masked because the customer just sees one labor and materials price. You'll notice it in slightly lower gross margins. However, if you don't have a consistent gross margin, you won't notice it.