Here's my dilemma, I need to replace a roof on one of my rentals and am debating on just paying a contractor to tear off the roof (it has a double layer of shingles) and cleaning up the mess, and then laying down the new shingles myself to save some $$$.

I am also getting quotes to install a metal roof, which will replace the shingle roof it currently has. 

For that matter, get a license yourself, hang up a shingle with a local broker and do your own listings.Multiple agents may sound good. 

The "new roof" is actually just new shingles over old.

Do I go the extra cash and put metal roofs on them or do I do a shingled roof and call it good.

Both of those are significantly cheaper than a complete unit.Water heater, installed, with supplies & removal of old unit is about $800, all in.For a 2,000 sq ft house, composition shingle roof, $14k at retail for the shingles.Foundation repairs can vary widely, but you can generally get it around $200/pier. 

This house is not that bad and not a ghetto; I have to replace a few missing roof shingles, fix some minor stucco cracks, replace the windows (18) so I can un-board it and do the interior updating so it can be rented.

I have a 1925 home (upgraded wiring) that has asbestos shingle siding.  

I just bought a small rental home that has asphalt shingles for siding.

Determining the capital components are fairly straightforward but determining what amounts you should plan for can be tricky as, for instance, the price of oil at a given time can have a dramatic impact on paving prices or roofing if you have asphalt shingles (and the association is responsible for it.)I tell my clients that part of the appeal of hiring a professional company to do it isn't just peace of mind that it's being done right by someone that does this for a living, but it also shifts liability away from the board to the company.