You get the point. One borrower was shocked when a private investor turned her down for a loan even though she had missed 19 out of 23 car payments and her rent was overdue for 11 out of 12 months. On a borrower such as this, I would not rent to them, buy a mortgage on them, in fact, I wouldn't even lend them lunch money. They will pay a higher interest rate. They know the value of good credit.
Payments are never on time.
They don't care about their credit. There are many considerations when investing into a private mortgage, but none is as important as borrower credit. Most investors are enticed into making a bad loan because of a high yield. There should be no excuse for taking risky loans with market conditions the way they are today. If the loan already exists, however, there is no limit.