I have noticed a bunch of customers installing Arlo systems lately. Apparantly you have to pull them down and plug them in regularly to recharge. 

Seems like a pain in the ass to me. 

I generally recommend against wifi based cameras as if they share the same access point as your internet connected devices, you will have a big wifi performance drop due to collision collapse. 

what is the typical battery life on those? (say Arlo Pro) ... I've seen suggestions of anything from a couple of days, to three months ... that's quite a variance!

I've purchased an Arlo system recently (3x cameras). I have mixed feelings about it.

On one hand, the hardware is pretty good, the cameras seem solid, small enough and are easy to set up. I like the idea of having a base station as (ethernet) as it avoid maitaining a wireless connection with each camera.

On the other hand, it seems like the system is let down by poor software or infrastructure. Things should be much faster than they are. It can take 20 secs to start live view, for example, which is frustrating. The Android app (can't speak for the iOS one) also seems sluggish with delays to refresh statuses, etc..

Regarding battery, you can opt to buy an external charger and a spare battery and swap out the battery when the one in the camera runs out. This would be much easier (and safer) than taking the camera down every time it needs charging. One alternative is to make sure you use at least one camera that;s plugged in and use this one to charge your batteries (and just swap out batteries as required). Regarding how long batteries can last, it depends on how much they get activated. The one on my driveway gets way too many hits (my neighbours seem to have a bazillion people living in the house, coming in and out) and wouldn't last much past 2-3 weeks. One that only gets activated every once in a while would last several months.

Would I buy again?  Possibly. I looked at other sytems (Ring and Nest, mostly) and all seem to have their own issues. But the system is quite expensive. I bought some Wyze V2 Cams (US$25 on Amazon) for the indoors and where I could get away with a plugged in camera to keep cost down. It does mean having mutliple systems but it also means I can afford more cameras...

Any question, let me know.

I have been using the Arlo pros for a couple of years now, I would look at something else purely because geofencing in their app is complete rubbish and fails to work most of the time.

The battery life is decent 2-3 months.

plas:

 

I have been using the Arlo pros for a couple of years now, I would look at something else purely because geofencing in their app is complete rubbish and fails to work most of the time.

 

The battery life is decent 2-3 months.

 

Agreed, geofencing is pure crap (although some of the alternative don't even have it). Fortunately, I implemented my own geofencing (via Home Assistant and presence detection using people mobile devices) so my cameras are being armed/disarmed based on our presence in the house which is preferable anyway.