Apartment building everyday of the week.

For a $900/mo rental, every day it sits vacant is $30 of lost rental income, and there's a certain percentage of the tenant pool that simply will not live somewhere that does not have laundry facilities available.

To me that's insanity, but it happens every day.

I'm not an accountant, but if you are going to use the tax assessment to determine the land value, then 1/6 (not 1/5) will be the land value, so the basis will be $83,333.

However, we now have added a second property to our portfolio with a good ROI that actually cash flows a little better than the first one and will make us more money on a monthly basis so still counting this as a big win! 

Air filters not being changed in years could burn out the motors faster as dust accumulates internally and in the vents themselves running to the air systems.You can also see in that time how the tenant is taking care of the property on an ongoing basis and any maintenance items needed that could cause potential hazards at your property.

That's definitely an individual basis questions. 

For pets just say that they are considered on a case by case basis or with owner approval. 

If you do it just go in knowing you will have to be there everyday to manage the tenants.

You could "creatively" call a "shed" an "ADU" and argue for a CO on the basis of "reasonableness."