So a toilet costs x, sink y, and tub z.The Residential Cost edition provides sf prices and 'assembly' prices also.

Keep your home at a comfortable temperature if you have cheap natural gas, you don't want tenants electric space heaters running all the time.Last thing would be toilets, and I'd do these only if you've already done everything else I've listed since they are either super cheap (aerators) or very effective (attic insulation).

Cleaners live in house and get free rent for trade cleaning common areas and toilets.

I recently had a tennant fail to notify me of an intermittently running toilet.

I have 30 toilets currently in my management and multiple toilets need some type of repair every year.

Don't give them a reason to squat and make it harder for you to get rid of them. 

This is the simplest method, but it also means your tenants are more likely to abuse the utilities by leaving windows open with the heat or A/C running, leaving lights on, ignoring the toilet that constantly flushes on its own, etc.3.

It also covers minor plumbing issues, such as clogged toilets and sinks. 

Gas has probably increased 50% over the past year.Remember, if I get a running toilet or any kind of leak, it can run up a huge bill very quickly into hundreds or even a thousand or more.  

The main costs I have questions about are linen services, consumables (toilet paper, trash bags, paper towels, tissues, shampoo and other amenities such as coffee/tea) and repairs & maintenance (R&M).