Companies managing hundreds & even thousands of doors use Buildium.Many of them though, use a CRM on top of it for even more features: Leadsimple, Monday, etc.Look into Appfolio, Propertyware and RentVine.

And the apartment is an upper that's definitely tough to move into, so the furniture transfer does have some benefits (saves a lot of banging around/removing of doors from hinges/etc.).

Why 100 doors?

Things to look out for are old windows, old wood siding, peeling paint on exteriors and interiors, and damage to window sills, door frames, and walls.  

You should have an understanding of what the per door expense is in the market, and then take into consideration the age/condition of the property.If you don't know what to reserve, have a few conversations with property managers in the market and talk to community banks who lend on the asset and ask themGino

The prices are more closely tied to the income they generate vs what the people next door paid for their house.As for your long term goals, I am not sure starting with a duplex or four plex will open the door for owning in that asset class (larger multifamily) the way you might think it would.

Right next door to my house there are 2 properties, both 6 unit 4 bed 2 bath apartments.

Building relationships with experienced wholesalers can also open doors to joint ventures and off-market deals, giving you a head start in the industry.

But the fact is that the teacher can open the door, BUT the student needs to walk through it!

Replace the glass for them (easy, two screws), or find a door off a used appliance that will work.