If an applicant came to you and handed you a printout of their tax return (knowing the blank forms are available on the IRS website and they could just fill one out in any manner they choose), and a printout of their credit report (which no landlord should ever accept from any applicant), said they were self-employed and make plenty money, but refused to provide any bank statements, would you be okay with their verbal assurance that they really make plenty of money?  

I would want them to be as sure as possible, so they didn't end up moving out or just being generally an unhappy camper.  

Once you reach a certain number of properties your lender will likely want assurance that his investment can not be jeopardized by an unrelated investment.

Lest you think we are taking it easy on one of our own, I can assure that the responses would be the same if there was a landlord on the forums up in arms because an otherwise decent tenant moved out owing $1.00.  

I say do nothing, let the lease automatically convert to a month-to-month, wish her well on her house hunt, and assure her that she is welcome to rent your property for as long as she needs to and remains a good tenant.

I can assure you this is not the case, although sometimes it appears that way.

While you may never fully break the bad habits, you can at least rest assured that you're providing a safe place for your elderly tenant and (hopefully) minimizing the waste of your time and expenditures. 

In real estate EVERYONE is a millionaire window-shopper until they put pen to paper and sign the check..... so don't bank on window shoppersI've seen ALL KINDS of promises and assurances made all the way up to the move-in date, just leaving only me in the dust.

They agreed to it, signed it and assured me (both of them!)

And you cali residents may live in fear of your judicial system in the peoples republic of cali, but I can assure you, I have passed along carpet expenses to tenants.