I flush the water heater yearly myself.Have spares for things.

I could go on more but I'll spare everyone.

@Joshua H. there is a bar with food trucks about 10 minutes away and they have a large spare room.

We are deep in a major renovation - so I have  been spending most of my spare time at the house. 

But, if everything goes the way it should, you shouldn't need to spare much thought for your investment - good turnkey investments don't require a lot of checking in. 

I'm planning to use a realtor lockbox for a spare key in an emergency, but I'm paranoid about the guests forgetting to put back the key when they leave and the next guest shows up with no key and no way for me to remotely let them in.

Please spare my friend the riot act, as they realized they took a risk and lost, and they don't plan to take this risk in the future for important jobs. 

As @Susan Robb correctly stated, property that qualifies for De Minimis cannot be considered an improvement to the unit of property (UOP) which generally limits the deduction to tangible personal property and components of tangible property (read: spare parts).  

Anthony, if you had the time to spare, that'd be great.Steph - I'm going to study that up real hard and apply it, thanks for the thorough info!

I would even be willing to pay a small fee each month for them to hold on to my spares.