From what I know, HydraFacial is a multi-step treatment — it cleanses, exfoliates, extracts, and then infuses the skin with serums in one session. A lot of people with dull skin see results after just one treatment, though regular sessions tend to build on each other. It's non-invasive, so there's basically no downtime, which makes it easy to fit into a normal schedule. Worth looking into if dullness is your main concern.