A curved shower rod is $30 and a crappy on is $10.These are the type of things that can matter to a tenant,  but round off to $0 when I do my math.Permanently installed shower rods (screws rather than spring tension) last longer and don't scuff up the wall as much.  

These cracks look deep and not something that can be fixed with cement.As a side note, it looks like there is likely leaks in between where the slab and wall meet so on top of doing significant foundation repair, you'll need to install an interior or exterior french drain.I am only going off 3 pictures so I could be wrong but this does not look like a cheap and easy issue to fix.

Therefor, I don't think you can give any general ranges for any of these items.It also depends on the quality of the item that was installed in the first place...and who did the installation.On top of that, items like furnaces, which demand maintenance (changing filters regularly) will have a shorter "shelf life" in rentals since tenants are notorious for not maintaining them. 

They have asked me if I would be willing to modify the bathrooms of the apartment, basically making them "handicap friendly", such as installing a walk-in shower with railings and such.

With real large windows like this, I'll often install a large picture window with an operable side panel.

In December more companies came it and we were told we would have to move everything off the floors or for a 1 day install when he chose to have them come in.

Don,Install a duplex outlet using RG6 (cable tv) and a Catagory 5 twisted pair cable (voice/data) to each location.

We're paying $2.00 a sq ft to install tile but when I have 3 guys at one location, they install 43 tiles or 96.75 sq ft (18x18) which is costing me close to $3.02 a sq ft (assuming 32 hours are worked ).

Instead, you can farm the work out to a place like Window World or any one of the other replacement window companies that do the $189 any size vinyl window installed deals, which frees your crew up for other work to be done!

John Blackman, very nice post, but I see HMLs lined up down the block that will loan 90-100% of purch+rehab (LTC), as long as the total is <= 65% of ARV and reserves are on hand to cover the initial rehab installment and pay the interest during the holding period.