I didn't find any information from the IRS, but found articles from several 3rd parties (custodians) that said it should be allowed.

You could try and just use third party sites like Zillow or Redfin but their information isn't 100% accurate and/or timely.

You terms, my price"Strongly suggest you focus on cash flow and it really helps to make certain the broker commissions are paid to lubricate and motivate all parties concerned. 

A lease works both ways and binds both parties.

If you continue to make it a win win for all parties, we all know that the repeat business will follow.  

However, if the numbers are on the tighter side then forcing the repair might be a good option to use and still close the deal.I would assume that if you were able to get responses from a number of others on the site they would probably say things like I am going to list here.1) Problems can seem small and simple at first but grow larger in a hurry - it happens.2) Depending on the type of shower/tub installed in the above unit it may be more than a simple fix and get into much more money than you think - you won't know until you open the ceiling for sure.3) After the plumbing repair you could be looking at mold potentially in the joist spacing area between units.4) Depending on the length of time the issue has existed and been patched to get by you may also have damage to the wood - joists between units and or sub floor issues under the upper unit tub/shower.5) If there is insulation between the two units, you may have soaked and degraded insulation that needs to be replaced as well - good news is that rock and insul are cheap to replace.6) OR......... you may have someone open it up to fix it and its just a simple plumbing issue and is a quick and easy fix - totally possible too.Just as an illustration, I went to replace a bath faucet for an accountant friend of mine yesterday.

The Original cash goes into the first, out the first into the 2nd, out the 2nd into the third, .............in the 'n'th, out the 'n'th (last), and it is never spent...just used "n" number of times.

hmm;  I sold doors & window for ~year and learned a lot - - also have an apt with casements - - just hate'm.Nail-up (ie new construction) need code inspection on the install, as the exterior needs flashing. 

Welcome to the party!

That is, if an owner installs an electric register or gas unit, which is supposed to be used as a secondary heat source and it's used as a primary heat source in the dead of winter..