I do work for friends & coworkers sometimes. Nothing extreme, just day jobs like brakes, oil changes, radiators etc. I charge $50-60 an hour. They usually say "that's it? You sure?" Not sure what a fair rate is. I want to give them a break but I also don't enjoy spending all Saturday greasy and sweaty. What do others charge? Shops in my area are all over $100 but even though I have all the tools, it's just my house... A miserable drum break job made me start thinking
Research what others charge in your area. If you want more work, you undercut that. If you have all you want, you match it, or if it's a referral, you can go a little higher based on the trust perception.
You wrote "a miserable job". If it takes more time, that factors into your billable hours. Is it possible that you just need more tools? A lot of times, the right tool makes a job so much easier, including the use of cordless instead of just muscle, or additional length/size/bends pliers, ratchets, swivels, etc, etc.
If you are only factoring billable hours for best case scenarios, adjust that to include the average over all jobs. Give more of a price break to the needy or family, less to friends and acquaintances who also tend to be less understanding and more demanding. Let the customer be the one hoping you will do the work instead of seeming needy and always be ready to back out if they want to run the show and tell you what to replace instead of what you feel is doing it right. Always do the complete repair with an estimate that includes that.
Your customer will be aware of the cost, and accept it or not. You can always lower the total bill if it turns out that some things don't need replaced, without complaint but raising it is a different matter.
I've written the above within the context of the type jobs you mentioned, where there is (based on your own judgement) less likely a liability if something goes wrong based on your skill level and understanding the issues.
You wrote "it's just my house" which implies these are all driveable vehicles being brought to you? That in itself does suggest a bit lower labor rate than a mobile mechanic would charge, but in today's market, I wouldn't start out lower than $75/hr and again this means the average for the type of work, not just your estimate based on every job being as easy as possible. Granted you are in SW CA, so at least you don't have remotely near the level of rust that some of the rest of us have to deal with, and that can make a large difference in ease of repair.