The only way to do it is to have a job where you can complete the work in less than 5 hours a day. Preferably one that gives you the freedom to leave early/come in late so long as you're doing well on your work.
No one actually works 8 hours a day and comes home to work 4 hours sustainably. I couldn't see someone doing that for more than two months without getting burned out.
This is very interesting. I'm not sure how my company culture would tolerate my leaving early, but it does seem like the most practical option for actually getting work done.
I feel like I probably have enough autonomy to do this, but it's tricky business.
Actually I have been able to do this pretty easily, but its probably because I commute an hour and a half each way to work on a train. So I get 3 hours a day to work on things I want to work on.
This has been my problem. I have spent my entire career at government contractors, so I need to record 40 hours of butt-in-seat time every week in order to make the auditors happy, regardless of the actual work done. That makes my days 10 hours from when I walk out the door to when I walk back through it, sometimes less if I spend less than an hour at lunch.
I've been doing that for 3+ years now. If you truly enjoy what you are doing in your side project it can work. If not, perhaps you are just doing it for the money?
No one actually works 8 hours a day and comes home to work 4 hours sustainably. I couldn't see someone doing that for more than two months without getting burned out.