This would also identify water table depth, soil liquefaction, soil expansivity (soil that expands or shrinks), or soil chemical content.

So many run from adversity and pain, they shrink away at the slightest prick of pain.

That's really shrinking the rental pool.But with the rental market expanding, given all the foreclosures/short sales/people afraid to buy given the depreciating real estate prices, one can still find a qualified renter without a pet.Me?

I hear ya and no offense taken or given but you might be in a small fast shrinking minority with this opinion as it has detached from the actual realities on the ground.

That said, as prices begin to correct, listing inventory may shrink.

This occurs whenever the economy shrinks like this. 

This shrinks the interior space further than it already is, which isn't ideal.

Is the population growing or shrinking?

If you take them out of the equation your funnel for new properties will shrink.  

Other options may be to restore/refinish the windows which I have a friend doing now and it works surprisingly well for old windows or there are also simple draft stoppers and shrink film that can be purchased relatively cheap from your local hardware store.3- Boiler is a bit old but if it functions properly you may have a few more years left in it.