Depends on your units role, your skills, where you are mobilised and in what capacity. For instance, if you deploy as a class 3 Signaller to Helmand province when a trawl appears on the notice board you'll probably not see any of your TA mates until you return. But you may deploy as a member of an infantry company to Bagdad, and be surrounded by people you know.
Plus if you have a required skill i.e. if you happen to speak Dutch, Farsi, Polish, Korean, Arabic etc, your skills set you apart and will put you in a specialised post.