Additionally, high-income earners with modified adjusted gross income (MAGI) over $250,000 (married filing jointly) may be subject to the 3.8% Net Investment Income Tax (NIIT).For 2025, bonus depreciation is at 40%, so consider leveraging it for eligible property assets like appliances or fixtures to accelerate deductions.

This sounds risky, are you being compensated by additional rent and have you checked with your insurance to ensure you are covered. 

Any additional will be refunded a few weeks after the auction. 

Local Facebook groups can be a valuable resource when looking for a handyman.

The landlord should be named on the tenant's insurance policy for additional protection and to assist with tracking compliance.

I am considering building up on my fourplex. 2 additional units.

If the water bill is $100 a month, increase the price by 20% (or whatever you decide is fair) to compensate you for the time required to split and bill and to cover additional use when tenants squander the utility.

Additionally, I wanted to begin using properties to pull equity to go towards buying more.

Be prepared to come in with additional cash to close due the the appraisal.   

I think the ease of use on the other OTA´s has skewed how people view Booking, but it is a really valuable revenue source IMO if you are willing to put in a little more work and deal with the occasional headache.