Quick answer: Use filter audiences for anything defined by attributes (“Dhaka branch”, “batch 2015”) because they update themselves; use static groups only for genuinely hand-picked sets like a task committee.
How it works
Filter audiences re-evaluate at send time, so transfers and new joiners are never missed.
Static groups freeze membership until you edit them — right for ad-hoc committees, wrong for departments.
Both kinds work everywhere: broadcasts, notices, dues campaigns and event fees.
Frequently asked questions
Can filters combine conditions?
Yes — units, roles and custom-field values combine into one rule set.
Do audiences show a live count?
The composer shows resolved recipient counts before you send.