1st step, going from 5 days / week to 4 days / week is pretty much a no brainer. You get 50% more free time for 20% less money. I did that 2 years ago and never looked back. Sometimes I switch to 3 days / week, then back to 4 days, depending on how I feel. But I would never consider a "full time job" more than 4 days / week. But sure, I am getting shit done, so I don't have a problem asking for that.