When (and when not) to discount
Discounting is a tool. Most owners use it as a reflex.
Discounts you can defend
Volume discounts where the math actually changes (you save real cost). Slow-season pricing if you can name the season. Loyalty pricing for customers whose retention math justifies it.
Discounts that destroy margin
'First-time customer' discounts that train people to never pay your real price. Across-the-board sales without an end date. Discounting to win a customer who's negotiating you down on every job.
If you must, change scope not rate
Lowering the rate is permanent in that customer's head. Removing a line item is one-off and doesn't reset the price.
Take your version of this question further
This is one operator-tested angle on the question. Your shop, your size, your trade, and your team change the answer. Ask your specific version inside Ask a Shop Owner to get a response grounded in how owners like you actually handled it.