Do you get the update notifications right after you have updated an app? Sometimes they are a bit delayed.
In regards to backup/wipe, I'd tend to make a backup every 15 days or so JIC. And it's my philosophy to wipe data and cache every time between different ROMs. I generally won't wipe, however, between just updating ROM versions (i.e. going from BBv0.3 to BBv0.4).