Yeah that's a solid point honestly. Used to think taking less money up front was just getting played. Saw a guy in my field do free small fixes for a few big property managers, and now they call him for EVERYTHING. Totally changed how I see those deals. Sometimes the smaller check today is just buying a way bigger job tomorrow.
There's another angle to this though that people miss. When you eat that cost and the client sees you taking the hit, it builds a level of trust that they'll remember for years. I had a client once where I soaked up a $700 overcharge on supplies because their budget was tight, and two years later when their neighbor needed the same type of work, they basically handed me the job without even getting other quotes. That kind of loyalty doesn't show up on a spreadsheet.