I urge you. If you want to be a success get out of that hourly rate frame of mind. Start bidding jobs on a contract price. If you say for instance think a bedroom will take 8 hours bid it at 250 plus material. Most people will feel more comfortable with that than an open ended Tand M arrangement. If you work by the hour it's a safe way to go but the potential for the occasional home run is nil. You need to make more than a wage at any figure. Even 25 or 30 is too low if you want to buy a truck or a spray rig where is the money going to come from? The exception would be a super custom job with a lot of unknowns like a squirrely decorator or architect. But you know about what it takes to paint a room or an exterior so stop leaving money on the table. You are setting yourself up for failure and lowballing us established contractors. I wish you well.