A price rise falls straight through to profit. Nothing is consumed on the way: the same work is done at the same cost, and the difference is kept.
This is why a small increase moves profit more than most people expect. On a ten percent margin, a five percent price rise roughly halves the gap to a fifteen percent margin, because the cost side has not moved.
What it costs
Volume. Some customers leave, and the question is how many, and which.
The arithmetic that decides it: at a ten percent margin, a five percent price rise can afford to lose around a third of volume before it is worse off. At a forty percent margin it can afford far less, because each lost job takes more profit with it.
Working this through requires knowing the current margin, which is what gross margin and break-even are for.
Signals that price is below where it should be
Winning nearly every estimate — see close rate. A close rate near the top usually means the price is not being tested.
Margins falling while revenue rises, which is volume without profit.
Costs having risen since the price was set. Materials and wages move; a price set two years ago is being charged against today's costs. See pricing adequacy.
Applying it unevenly
A rise need not be uniform. It can apply to new customers only, to the least profitable work, to a particular service, or to jobs beyond a travel radius.
Uneven increases are frequently better than a flat one, because they raise price where it is least likely to lose work worth keeping. Which work that is comes from job margin.
The same arithmetic run backwards is discounting, where the concession comes entirely out of profit.