The whole "paint my car in my shop/garage" thing is a "boil the frog" journey. Good to be aware of that up front.
It starts with "I need a spray gun."
Then "oh, I need ventilation."
Then, "a 3M respirator isn't enough protection, better get a fresh air hood."
Moves to "crap, I have a Harbor Freight water trap and really need a good filter/desiccant system or air dryer."
First primer shot and I say "wow, I couldn't see anything while I was shooting, need better lights."
And it goes on . . .
It's all worth it to some (me!) but not everyone.