How often? In principle at least once a week when you send a mail merge.
Otherwise daily look "movers" tab and the "genealogy".
They CSAs something trying to get them send the question of what they need?
I look at the VP Ledger and see where the "deadlock" or forgotten entitled to VP.
Of course I take care that each CSAs has its Sponsor.
I suppose he conscious of their group where "my" CSAs still sponsor's PSAs!