What does "per door" mean?
A "door" is a single unit or home — one apartment, one house, one condo. "Per door" is a way of counting or pricing by the number of those units, rather than by the number of buildings, people, or accounts.
In plain terms
If you run a 40-unit building, that's 40 doors. If you manage three small properties of 10 units each, that's 30 doors. The door is the thing the work actually happens to — rent or dues come from a door, a ticket gets filed against a door, a lease or covenant is signed for a door — so counting by doors counts the real size of the job. It's the industry's plain unit for "how much property is being run."
When it comes up
Constantly, in two places: describing the size of a portfolio ("we run about 600 doors") and pricing software, where per-door pricing scales to the size of your operation instead of charging per login or per building.
How Arbor Lane relates
Arbor Lane prices per door, because the door is the unit the work maps to — Non-Profit at $1.50 per door with no minimum, or Pro at $2.50 per door ($20 a month minimum, stepping to $2.00 at 200+). You pay for the doors you run, not for how many people log in.
The words are half of it. The work is the other half.
Arbor Lane runs the dues or rent, the documents, the governance, and the maintenance — the things behind every term here.
Less time on the busywork. More on the people.