wrote this at 4am here while I'm waiting for the server to restart haha
the detailing market is a tough one to answer that question for really. At a high level, as a 'great' source of income? No. Not exclusively the answer but:
Like any business, in terms of profitability, you will need to take in to account what sort of level you want to go in at, costs of equipment for that level, consumables etc will be on a sliding scale accordingly. When you want or need to see a return on your investment dependent on how you'd finance it, ongoing costs etc, what the market is in your area.
When you say detailer, do you mean simply sprucing up cars, wash and hoover, or more involved paint correction. If the later what training and insurance are you going to need to make sure you don't cause more harm than good? Then you've got advertising costs and promotion to get yourself exposed etc. Are people going to really pay for people to wash and wax their cars at a given price point? maybe the mid level office worker sort of level, company cars getting a once over while at the carpark. Spending less than that, people will go to a car wash or do it at home, any more and people will be paying a specialist to care for their porsches etc. Are you going to enjoy washing and waxing that sort of level, doing a load of 3 series in 30 mins or less for 20-30 a car? Try to throw in too much in the way of extras and you'll eat your profits due to the extra time required and equipment and consumables. Charge too much more and people will want more.
Problems with it? Barriers to entry? Not many. Anyone can buy a cheap mg or fiesta van, an oribtal, put some ads up and print cards and go into it. Yeah experience and training is the difference between a car washer and a fully fledged detailer, there's no pre-requisites to stop anyone doing it ie giving you competition.. When things are bad, it's a luxuries that many won't take on, the ones that will will either be bargaining for price or going to a well-established company. That may seem like an opportunity, but will the bartered price be worthwhile for you?
How many people are there in the area doing it? more competition means more bargaining power of customers.
You can't simply approach it by seeing the prices that local companies are charging; they are established, you aren't - which means they have constant possibly repeat business/word of mouth, (likely) cheaper overheads per capita etc. If you build a model around undercutting them without being sure a) what your expenditure will be and b) that you can compete even in terms of service provided, could mean you end up making much less than you think. First work out your costs and requirements - then how many cars you need to turnover to meet that cost. Only then you can establish a rate - Will this be on the weekends so any extra cash is a bonus? At what point does the extra profit in the pocket become worth it for you? 100 a week? 300 a week? 1000 a week? then you can work out at your given cost how many cars you need per week, how much markup you can apply, have a look at what profit that per car rate generates, and how that fits with what you need to see as profit. Like I say if you enjoy it and just want an extra 100 or 200 a lot of this may be overkill - if you're looking at it as an actual substantive income, and need that figure to be 500, a grand, 2 grand or whatever then it gets trickier.
Not being negative, but it's one of the many businesses that you have to grow slowly before going in and hoping to come out floating with great turnover.
Usa