I only buy the Aquasource Henshaw White Watersense Elongated Height 2-Piece Toilet from Lowe's (item number 98923 model # T802).

Also, how old are your capex items? 

If so, are you concerned about Spain's tax system on worldwide items?

This is true for bonus depreciation items as well.  

But, there are certainly several items that would give me pause.  

It is not your responsibility to house this person's items indefinitely in your rental. 

I'll Google those items and see what I find.

Once I get to a point that it is making enough per month that I feel comfortable taking money out of the business that would be when I get to the point that it is worth have a specialist assist me in all deductions, credits, and future items that will help me to transfer from a W2 to working for myself fully.

Due to item 1, adding an ADU can require years to start achieving any return (once the accumulated cash flow recovers the initial negative position).4) Adding an ADU is a slow process.

I will always look at the air handler and make sure tenants are installing fresh filters (most neglect this item).