OK...let me chime in a little. I detail full time to put food on the table and pay bills. I will post more later too.
Let me start off with your low number. 150 cars a month. (doing this considering the weekends off)
52 weeks a year....2 weekend days in a week. That runs you at 260 WEEK days.
Take that 260 and say you do 2 a day...that is 560 cars a year. Granted, you may have days you do more or less.
Now, you were looking into 150 cars a month......well go the highest, and do 31 days a month. Working 7 days a week. 150 cars, divided by 31 days is 4.83xxxxx cars per day...so, rounded up...5 cars a day. All cars are different in condition. Some will take longer, and some shorter. 5 cars a day at say...a max of 4 hours a car, no breaks in beween, is 20 hours a day. Then figure in your travel time to each destination, breaks, eating...etc...... You are well over 24 hours a day..... That is for details.
Now for washes, you need to figure in what amount of time it takes you to do one. It takes me an hour and a half to do a wash and vac by myself. That includes, setup, wash vaz, wipedown, tires, rims, windows, and whatever else. I do not make much on washes, so I try to upsell details. 60% of the time, the customer bites and buys a detail instead.
You need to figure in time to the destinations. The more cars in one spot, the more money you will make.
I am currently doing 1-2 cars a day. if 1 car, I will try to get a few washes in there around that location. to make a few extra bucks.
I am not bashing or talking down to you. There are many variables that you need to factor in. Your area is different than any other area. When I first started, I had hopes of raking in the money quickly. Once reality struck, I sat down and worked out a few plans. Being mobile, you need to hustle. Word of mouth and your rig will be your best form of advertisment. I only have cards out at 4 locations around town, the rest is word of mouth. Being 1 man...I only want to do 2 cars a day max. Any day off I have, I try to relax.
I really like your attitude towards this line of work. Keep your head up, and it will fall in place soon. When I first started, it was VERY slow. There were actually full weeks when I had nothing. That is where you hustle.....
I will touch on this more later.....I need to run and get a hair cut...I look like a wild man!!!!!!!!!!! Appearance is a must!!!!