So I've adopted three lovely cats, but they are not yet home. They don't wear collars at all currently - they've been in the adoption centre for ages (2 since Jan and once since April) and one of them was a stray before that - the other two were quite young and I don't know a lot about their history.
They will be 18 months when they come home (I thought adopting would take much longer due to a busy road and a four year old but actually we passed the homing process quickly - I'm a very experienced cat owner luckily - and now have to wait to get back from our holiday before we bring them home).
So I guess the best thing to do is to start with a normal collar for a bit - I'm ambitiously hoping to keep them in for a few months, they are all or mostly black and we will head into both Halloween and fireworks season and I'd rather not let them out until I know how they will cope with both.
I'm not keen on them roaming, and whilst I'll cat proof the side gate to prevent access to the front I won't stop them roaming the surrounding gardens (it wouldn't be possible to proof the whole garden due to trees) so I want to know where to find them if they disappear.
I did see Tractive whilst looking, and saw a lot of people mention losing them, and that they don't work inside buildings etc but I think you can see their last movement before signal is lost. I also saw Pettracer which looked less bulky but it's hard to know what actually works.