Free Grow AI is the right default for most posts: it optimizes discovery organically, worldwide, at $0, and builds the audience data that makes later boosts cheaper.
Paid Boost earns its budget when a post has already proven itself — strong retention, saves and shares — or when timing matters: a launch, an event, a seasonal moment. Boosting an unproven post mostly buys you faster disappointment.
Virello's rule of thumb: let Free Grow test the content; when the AI Growth Score and engagement rate beat your niche average, a Starter or Growth package can multiply what is already working.
