Comment by kmoser

Multi-decade permanent contractor here (software developer). Some of it is luck. Some of it depends on the nature of your industry. Also, OP seems to enjoy learning new tech stacks, which makes them attractive to more owners of screws that need replacing, thus increasing their marketability.

It doesn't hurt to occasionally beat the bushes and ask your friends if they need screws replaced, or if they know anybody who does.

Short answer: if you replace screws efficiently and communicate well, you will become the go-to person for replacing screws.