Beyond checking individual key return, test connected key combinations (like the low C to low B to low Bb chain) to make sure linked keys move together correctly, since misaligned linkage is a common issue after a drop or rough handling. Hold the saxophone up to a light source and look through the bell while gently pressing each pad closed; light leaking around the edge of a pad means it isn't sealing and will cause that note to sound weak, airy or not at all. Cork and felt bumpers between keys wear down over time and affect both key height and quiet operation; visibly missing or compressed cork is a normal, low-cost fix during a routine service.