NaillyA refill (or fill, or infill) is the maintenance appointment for an ongoing set: the tech fills the gap of new growth at the cuticle, rebalances the structure, and refreshes the surface — keeping the same enhancements on rather than starting over. Because nails grow about three millimetres a month, most sets want a refill around week three: partly cosmetic (the gap shows), partly structural (as the nail grows, the product's weight moves toward the free edge and the set becomes progressively more leveraged).
A standing refill schedule is cheaper — in money and in nail health — than the rescue appointments that follow week-four breaks. It is central enough to nail life that Nailly builds the window in: artists get a nudge as each client's set approaches the three-week mark, with a one-tap invite back to the chair.