Everything spelled out in language a 5th grader can understand. 

That soft quote needs to be accurate enough for you to make a decision and it should be spelled out what the contingency is.  10% is usually about right. 

She seemed ok with it, until I went to collect rent today and she's claiming she cannot find the letter and that since we spelled her name wrong she doesn't know who that person is. 

I also have some rental properties in NJ and my lease agreement is pretty thorough and spells out the expectations of rental payment. 

But I 100% believe that it will help build repore' (not sure I spelled it right) with your contractors.  

Some of the reviews I read on here call out the poor grammar or spelling errors, etc.

In CA all multiplex units are rent controlled and lease can only be terminated for a few reasons that are spelled out in the rent control regulation.. 

This spells out the sell or rent of the existing house, alimony, child support...

"I didn't know that" is not a valid excuse for late payments, unauthorized animals, unauthorized painting, or any of the other multitude of items spelled out in the documents.

In the future, your lease should have rules specifically spelling out the consequences of bullying, harassing, invading private space, use of other's personal belongings, noise, and many other roommate situations.