Security and ease of access are the main two.
I have containers, full cctv, easy access(usually), etc.
The internal places can be great but not always that easy to get stuff in and out of depending on the layout.
Plus though is its inside so if you’re having a shuffle you don’t get wet but you can get other users wanting to get past, etc.
Although had it recently where the container 4 up decided to have a sort out and literally covered the entire frontage with shit – blocked access to 20+ containers and they were properly shitty about moving.
Refused to actually!
We just walked over everything to then start dragging large lumps of metal and tools out – they soon moved – surprisingly quickly for a bunch of Golightley’s 😆
Get the smallest unit you can get away with – they can get pretty expensive – we moved some rubbish into one temporarily whilst doing some building work – ’twas £250 a month IIRC. Sure there’s some ones a lot cheaper though.
Do you need 24/7 access? Can’t imagine you do.
Having some trolleys was useful for us to cart stuff around, and the little ‘un was very excited to go in one of those old style lifts with inner/outer doors and the walls moving past you.