None of these factors operate in a vacuum, but instead they operate in concert.

I only have maybe 10  the airlines I fly.. 

AZ and other places that were created and sold in those days.. it was a huge industry that pretty much died as land use laws became regulated.as for being a top gun I wanted to be an airline pilot but had to settle flying myself and buying my own airplane to live the life I deserves as a Real Estate broker investor/ lender/ builder/  BP nut

Pulled out that carpet and it looked like it was never vacuumed in ages. 

One issue with the splits is that even though the install is easy you still need a professional to vacuum the lines.

Do you have a vacuum in each property or does cleaner bring their own?

Outbuildings didn't have to be touched beyond basic clean out.I agree with others who have stated that plumbing and electrical can get you, but it's so worth working with a jack of all trades general contractor who knows her/his stuff and you know codes so you can give very specific direction and have them get the job done without having to use a full-fledged plumber.The following has nothing to do with your question about biggest expenses, but may save you big dollars in the long run:We were given some tips that have paid off: vacuum out your HVAC system to the best of your ability prior to inspection (inspectors see dirt or dust and they give you poor marks and tell potential buyers that a professional needs to be brought in to clean out the system); run Draino through your tub/shower drains (if you're leaving existing tub/shower in tact) prior to listing and test the drains to make sure there is good flow (we might or might not have used the tubs to clean paintbrushes, which resulted in REALLY slow drains); If you have a hand dug or shallow well, run bleach through it (lots of instructions online as to how to get bacteria out of the system when a hand dug well is involved) and flush the bleach immediately prior to inspection.I hope some of this helps. 

If you have the cash, do it right, and you will save on more that your tenant's temper.I had my attic vacuumed of all old insulation.

The goal is to potentially begin a family once I have established basic seniority at an airline.

I do know that in most industries the top producers or users or buyers do get some perks.Its in all industries.. think about the airlines..