You MUST invest in income-producing assets and ventures.NO ONE EVER "GOT RICH" swinging a hammer or a paint brush!

that depends on how good you are with your paint brush.

Originally found BP from the podcast which like @Hadar Orkibi a mate of mine locally, I listen to religiously and save a number of episodes specific to my interests to go back over when I find time on the end of a paint brush ;-). 

Gutter pieces, fittings, hoses, knobs, valves, vent covers, trim pieces, paint brushes, screws,...on and on We spent 3k just on dumpsters and cleanup.  

I do respectfully disagree with @Jay Hinrichs broad paintbrush stroke of renters in the price range being unstable - in a small town like that, you'll find a lot of good people and not all are poor working for $8/hr.  

BTW, try using a hammer and a paint brush instead of a computer and a printer.

Much less actually pick up a paint brush or a screwdriver. 

Some buyers want to do nothing and are afraid to pick up a paint brush, so this will help alleviate that. 

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. 

You never have to pick up a paint brush to rehab or unclog a toilet as a landlord as the tenants are long time owners.