However, they said with the pattern of being late for 3 months in a row, and with the increasing number of late days, and the increasing amount unpaid each time, that a pattern was forming, and they recommended that posting the notice was needed to let the tenant know it's not okay.  

First paying $600 for Mold Inspector report , next going to her doctor to get reports and last nail take the reports and filing a court case.My Realtor says he is seeing this pattern on few other rentals where they try to extort money from Landlords.

If tenant's credit report shows a consistent pattern of late Payments to other creditors - you can expect they will attempt the same with you.  

Patterns, history, useage, maybe even include that car payment in your analysis of if they can truly afford your place

Look at outstanding debt and payment patterns.

Applicant’s background must exhibit a pattern of responsibility and law-abidance.

Otherwise you will be a landlord that more success landlords buy property from for pennies on the dollar.This late pay pattern compounds over time and units.

All tenants with bad credit are working on repairing them or had their identity stolen - rather I look for the pattern of behaviour.  

The nice thing is that if a section gets damaged, we can cut that section out and a new piece with the same pattern and it's a perfect fit; you are hard pressed to see the repair and if water spill on the area, it's still sealed.  

You've got folks that want a $600k home, so they look at homes listed for $500k to compensate for the pattern of stupid asking prices in our area, but your home looks crummy compared to the $600k ones... because it's a $500k home, which is why you listed for $500k!