Do I need dust extraction or is the included bag enough?

Across verified-purchase reviews and woodworking subreddits, the near-universal verdict is that onboard dust canisters and bags are mediocre at best. Hooking the sander to a shop vac (often via an adapter) dramatically improves dust capture, reduces airborne fines, and helps the abrasive last longer. Plan on a vac hookup for any serious indoor work.