This is possibly a world first. I find it hard to turn down work, because the twin draws of money and experience are irresistible to me, and I feel like I'm letting people down. But today I turned down teaching work that was not only amazing experience (teaching on a TESOL MA course) but worth around £1400. That's a heck of a lot when you're in the last (unfunded) year of a PhD with no savings.
I would have loved to do the MA teaching (there was also some other teaching that was more appealing for the money than for the experience, though it would have been another string to my bow - discourse analysis, which I'm not sure what it is, and I don't think it's real linguistics, but apparently it's a thing), but it was just too much work. It was the phonology component of a linguistic theory module on the TESOL MA. I'm not a phonologist by a long chalk, but I've been teaching quite a bit of it so I can get by. But for an MA course, that's quite a lot of preparation, which eats into the (generous) hourly rate. Then there's the assignment, which requires them to transcribe their own speech. That means that I have to teach them phonetics as well as phonology (even more not my thing) and also, marking it means checking their transcription. This is a thing that takes a Long Time. So, regrettably, I said no.
But on the up side, that means I have more time for thesis-writing. And I've still got some teaching, just not that teaching.