I've found that the threshold depends not so much on number of APs but on number of simultaneously active users/devices (arguably the ratio of those per AP, rather than total).

An office of 30 people sharing 3 APs will encounter problems even if those same APs would have worked just fine for a family of 4 living in the same space.

I've even found this to be true in a residential setting with consumer APs, where reducing the number of devices (by plugging into wired ethernet things that don't often move, such as media players and printers) tends to improve range and throughput for others, without adding more APs.

I sincerely question the value of a managed wifi system for less than 5 hotspots, I also am even more dubious of the need for a cloud service. wifi should function without the need to phone home.

> I sincerely question the value of a managed wifi system

I'm not suggesting that there's necessarily value in "managed", but your parent comment was about the Ubiquiti product being overkill, which is a much broader statement.

The GP certainly advocates for management, but that's neither the primary value delivered by the overall product, nor the majority cost (even with a single AP). IIRC, this may not hold for competitors, such as Ruckus, where even the lowest-end "controller" is quite pricey.

> wifi should function without the need to phone home.

AFAIK, Ubiquiti's products can be run standalone, only requiring management software for initial configuration.

> AFAIK, Ubiquiti's products can be run standalone, only requiring management software for initial configuration.

This is correct. I only power on the controller VM when I want to make a change. I do think a few features, like the captive portal require the controller to be online.

No, this is where they really shine. Ubiquiti is often referred to as “enterprise lite”, where if you really need scale usually other options are better. But at a small scale, they are excellent.