Blue Tit Nest Box Behaviour

Hello,

I put up a bird box last year - in April. A blue tit visited the bird box the day after it was put up and I didn't have any activity in the box until January this year.

Since 4th Jan, I've had what I assume to be same blue tit(s) visit the bird box regularly. I did once see one bird fly out, then a different blue tit fly in on one occasion but otherwise it's difficult to tell if they are the same birds going in.

They've been in the bird box most days and seem to look around for a little bit, before leaving (and sometimes coming back on the same day to do the same thing).

It looks as though they are inspecting the box but I'm just wondering how long does this typically happen for? Is this them scouting a potential nesting or roosting locations and if so, should I expect this behaviour to continue until March/April when they should settle on a nest location?

Attached a video from today for reference.

Many thanks