I also put coin-op washers and dryers in the basement of each of my buildings.

I think it was the book "The Millionaire Next Door" that coined the phrase stealth wealth.

Should I keep them in unit, replace with one coin-op, or remove them completely?

Also, considering adding coin washer and dryer. 

I love the coin-operated washer dyers for multi-units, kinda off-sets the cost of the water bill, that is if you are responsible for that.

Even at regular rates it is almost a loss leader business where you have to do volume just to make a little coin. 

In my duplexes I provide a coin op washer and free dryers. 

I would love to hear other sides of the coin. 

Sounds like you faired better than the donut shop on Steuben Street.http://www.wtae.com/news/car-crashes-into-better-maid-donut-co-in-elliott/32377260

With me being a renter, I definitely see both sides of the coin in respect to whether or not to increase rents or keep them the same; especially if you are currently under market value.As a renter, if my rent increased every other year about $25 or so dollars, I'd be fine with it; however, if my rent increased every year arbitrarily because they "can," then I might be more apt to look for another apartment, even if the new apartment was a comparable price.