Hey Cami,If you use the search function above you'll be able to find a ton of threads with great marketing information (I've probably repeating this marketing information a gazillion times).But... here's some advice:1. 

@John ReedOne of the advantages of a solo 401k over an IRA, for example, is that, as the solo 401k trustee, the business owner can perform managerial functions.

A spce must function other wise you wasted your money.  

But, absolutely the best advice you have been given and I totally agree is to find an REI meeting, club or networking function and attend.

They seem to be still functioning but I was wondering whether I should start replacing them or wait longer.

These investors have a very robust stream of other income and are looking to shelter that money until they retire and can slowly sell off their portfolio which will be worth a lot more money 30 years down the road.

If the septic field has been functioning fine then in most cases I would assume it will pass an inspection.

If it is left out of the SOW, I assume it isn't considered in the "as completed" appraisal. given this the bank says that the house, when finished, will have non functional plumbing and electrical systems (because they were non-functional upon purchase) and thus isn't worth anymore than I paid for it.

The 1960s buildings have some functional obsolescence in my opinion..Where as the buildings Built in mid 90's around here have pretty much identical layouts to the new buildings so when I do upgrades the incoming tenants can't see much difference.)Hope this helps.Peter  

Quality and consistency of cash flow (which is directly a function of the quality of neighborhood and tenant base) as well as equity position and capital reserves matter tremendously, more so than amount of positive cash flow IMO, in mitigating these situations.