The instructor said that Joy (or similar brand) dishwashing detergent mixed in water is more effective at removing mold than bleach.

Also, you need to decide who is responsible for stocking and paying for paper towels, dish detergent, and toilet paper (if there is a shared bathroom), all those kinds of things.  

In my STR I have a washer and dryer, and supply detergent, so guests can wash them if they want.

, a few incidentals like dishwasher detergent.  

Things that is out of my hands such as the building intercom that the association is working on replacing and how there’s powdered detergent in the dryer in the building laundry room.

We have dealt with that & also panty stealing & theft of each other's laundry detergent. 

And a non-trivial amount of ongoing expense - water, detergents, maintenance, cleaning, etc.

There is usually no timer based coin-op for washer, they are programmed to pay per wash cycle. 10 minutes isnt long enough to rinse out the detergent anyway even if that was a thing:) Only dryers pay by dry time, but usually even those usually require a default 40 minutes for example and extra quarters would add increments.

I do use bleach after washing to spot treat anything that got left behind stainwise.There are some comments about stains not coming out, but I am guessing they don't use a premium detergent.

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