If you are cash flowing $200/door and you want to make $20,000/mon then you will need 100 doors.

Contractor is being patient with her and trying to talk as to why she's not opening the door.

that we’ve learned in our 24 years, managing almost 700 doors across the Metro Detroit area, including almost 100 S8 leases.

For your long term success it does not matter as much if you have 10 doors or 100, as if your portfolio value is 500k or 5 million. 

Tenants don't read the lease and if they do they forget about the details soon after.Instead, post something like this on the inside of the bathroom door:

If your intent was to hold onto the property and a bear moved in next door (True Story) or maybe you receive an unsolicited offer you couldn't refuse, so you decide to sell.

Initially she was very happy and excited but after a day, she had a disagreement with the contractor and now she's not opening the door for the contractor to come in and finish the work.

that we’ve learned in our 24 years, managing almost 700 doors across the Metro Detroit area, including almost 100 S8 leases.

If there is just a smart lock on the door I don't think they need the key.

They also said they see this problem ALL the time in Philly… when the city or a private individual knocks down a rowhome, they are responsible for treating the exposed partition wall of the next door property to protect it from the elements.