Interests rates where above 5% in 2006. no crystal ball but surely there's a year or 2 to go however i suggest it wouldn't  do any harm to start watching the monthly stats a little more carefully.!   

I don't like to get in the habit of trading rent for property work but if they have been actually doing it for 40 years they have a case to listen to.

Very true @Dennis Mears, the market could support probably 250$ more based on my research (only 2, 2 bed houses for rent in the whole city, and they are going for 200$ more than my proposed $150 more price.) but vacancies are expensive and having them been there 3 years they must be decent, just some bad habits from previous landlords 

If not, I walk away , no harm done.

The landlord shall at all times during the tenancy maintain the dwelling unit in a habitable condition.

No harm in asking and finding out.

It actually harms them into believing certain things exist and they can get their hands on them. 

If not, will you be liable in the future if any damage or harm comes to him or future tenants? 

It’s a habit and I don’t even miss the money.  

Overall, each town and each investor will need to pull together a number of options to create what everyone deserves - a clean, habitable home that doesn't bankrupt the family vs. a reasonable rate of ROI... not easy - but "doable".