Generally speaking, these items break when they are working hardest and they of course are working hardest on the hottest and coldest days.As Patrick mentions above when you have to replace in an emergency you always end up paying more for a variety of reasons.

The nice thing also about all of these items is that they are all plug-ins, so no battery changes needed.

Within two months, my wife and I received vulgar text messages from our former neighbor complaining about the tenants and noise.While fixing some items at the unit, the other neighbors on the block noted how great our tenants were and how appalling our former neighbor's behavior had been.We received word yesterday that our tenants will not be renewing their lease and are seeking to break it early - noting that the neighbor is simply intolerable.

When wondering if a short-term vacation rental is a good investment for you,  first decide if any of these items meet your investment goals:  Is it your dream to own a property in a vacation destination?

I’ll be looking into each item you mentioned.

If you're self managing, I would charge myself the management fee so it's all clear and itemized for his auditing.

How to calculate these items in your market might be a little different than my market. 

They leave trash and personal items in the hallway and don't respond to notices to clean it up. 

whether an item can be expensed depends on if it is ordinary and necessary(and reasonable).It would be hard to argue that a random MBA is ordinary and necessary to your business.Maybe a class that is very specific to your business.

After our first tenant moved out I noticed that I couldn't find the scratch anymore.Floors are probably the highest wear item so personally, I would hesitate before buying a budget product, especially if it is not advertised as waterproof.