Minor cosmetic repairs have to be made and there is a value add opportunity with the addition of a condenser for HVAC.

Then in July the same AC was having problems, and it turned out to be the condensation pan was leaking, which caused water damage to relays and other mysterious AC parts.

For the mini-split I was considering dual zone, but again, that would still require multiple installations even though there is only one condenser.

Now this is just a VERY condensed reason , which there a ton , on why you should or shouldn’t incorporate.

General cost for a Furnace and Condenser swap out?

The philosophies in that book are very similar to the BiggerPockets methodology condensed into one book.

The condenser in my outside AC unit was stolen (there is literally nothing inside the case).

The two most likely culprits: lack of bathroom ventilation or general window condensation during extremely cold temperatures.

The company that did the repair did not braze the line properly and all the refrigerant leaked out and with the tenant being gone for a 4 day weekend the compressor locked up and just like that a new evaporator and condenser on a 6 year old unit. 

This is what one company's tune up entails:Spring AC tune up:Indoor Unit*Blower Motor *Amp Draw *Bearings *Blower Wheel Balanced *Control Board *Operating Properly *Incoming Voltage*Connections *Low Voltage *Electrical Connections *Change/Clean Filter *Capacitor *Thermostat *Check Operations *Outdoor Unit*Compressor*Amp Draw*Condenser Fan Motor*Amp Draw*Bearings*Capacitor*Electrical Connections*Clean Condenser Coil(water)*Check Refrigerant Levels*Check Contactor *Relays Operation*Check Operations*Clear Condensation Lines*Furnace:Fall Maintenance Checklist*Replace Filter*Electrical Connections*Check Thermostat*Verify Blower Condition*Check Control Operations*Check Control Board*Check Capacitor(s)*Amps of motor operations* Check Relays*Heat Exchanger Condition*Burner Condition* Remove and clean flame sensor* Inspect Blower Wheel*Inspect and check ignition operations* Check ALL safety operations* Verify a good clean burning flame*Are these pretty standard work supposed to happen for tune ups?