Learned how to use a pnematic nailer, and became a great painter.

Also, always change your unit's HVAC filters or you be going through heat exchangers, evaporator coils, and compressors more often.  

BUY quality SINGLE FAMILY homes SFH.that appreciate.4.Always do a home inspection using a certified home inspector ( with utilities turned on) and separately  hire an A.C. company to thoroughly inspect the state of the HVAC ( it might be blowing cold air today , which passes a home inspectors test) but the coils might be shot and the system riddled with leaks and crushed air handling tubes.

You may not need it if you have a Paslode nailer, but for circular saws and reciprocating saws you may.

A new coil for an air conditioner would cost $2K-$3K, good luck getting even break/fox plumbing work done under $1K, etc.

At some point, you'll have to replace roofs/water heaters/ furnace/ AC coil/ upgrade kitchen and baths and the rental income needs to be able to support it.Property analysis should include PM.

For AC, you need separate ductwork for supplies and returns between the units, separate blowers, and you also need separate cooling systems - condenser and coiling coil; you might be able to use mini-split units to achieve that.For hot water, you need the piping separate for the hot water, and then you will need multiple water heat sources with one per unit.

Then I'd fill in the middle sections at points and drop a cap made of bent pieces of trim coil over the whole thing.

You may have issues with residue in the hvac coils or vents.

Same with the AC, Cleaned the coils inside and out and replaced a faulty fan motor but did not replace it so I'll need the cap-ex money eventually.