You'll probably be stuck at "your little wash" forever because you've got to be on hand when currency is used and you can be there to count it.I'm dubious about more profit gained due to 'tokens only'.
Yes, you can train the customer, but it is still the wrong view point, to me. And I am including myself in this, because I was formerly 'tokens only'.
Being at the wash every day, I learned just how many customers came in with quarters for the SS bays; it was ALOT. Yes you can train them, but you are still neglecting the infrequent or one-time-only customers who have quarters only to spend for some reason. Some customers from out of town, for example, would not qualify for training.
Any lost sale matters to me and my little wash, so that's why tokens and quarters (and soon CC!!) works for me.
To each his own.
Tokens only afford basic "no no" to thieves whether they come from outside or from within, your employees. When there's no cash involved except what goes into the token changer life becomes simpler. The meter on the bill changer records exactly what went in and that's how much must go to the bank. You can also count the tokens in the bay boxes and that should be reasonably close to the amount of tokens that were exchanged for bills. You don't even have to be an on hand owner if you have someone trusted to empty the bill changer and take the funds to the bank. You don't have to separate quarters and take the bag to the bank and get charged by the bank for counting them. When you buy tokens for 40 cents each and sell them for a dollar you're suddenly in a new business of making money when the tokens disappear into never never land, you know, the same place where socks disappear.
When you get your second or third location you'll have a relatively free mind with "tokens only". Trust those that have been doing this for 28 years. Good luck to you!