A random orbital sander with a worn backing pad gives itself away in three ways: the abrasive disc starts curling at the edges, the dust extraction loses bite, and the finish picks up small swirls or hot patches. None of these are abrasive problems — they are pad problems, and a replacement sanding and polishing backing pad usually transforms a sander that felt past its best.
Three things matter when ordering. First, diameter: the common sizes are 125mm (5”) and 150mm (6”), with a smaller market in 90mm detail sanders. Get this wrong and the abrasives won't sit flat. Second, hole pattern: 6-hole, 8-hole, 9-hole and 17-hole patterns all exist, and the holes must line up with the abrasive's holes or dust extraction stops working and the finish suffers immediately. Third, stiffness: harder pads cut flat surfaces faster and hold a crisp edge, softer pads conform to mouldings and curves. Most factory pads sit in the middle on purpose; if your work is mostly one or the other, a dedicated firm or soft pad is worth keeping alongside the original.
Pad attachment is hook-and-loop on every modern sander we see. The hook side wears out long before the rubber does; if your abrasive discs no longer cling firmly, the hook has gone and a replacement pad is the only fix. The four small screws underneath the pad lift it off most Bosch, Makita and Festool sanders in under two minutes.
Abrasives matter too. Aluminium oxide for general wood, silicon carbide for finer finishing and lacquer prep, ceramic for hard hardwood and stripping. Grit progression matters more than total time — 80, 120, 180, 240 will almost always outperform a single 180 run, regardless of how long it takes. The full sander consumables range sits under sanding and abrasion.
If the sander itself is running hot or vibrating harder than it used to, check the brushes before blaming the pad — the major brand fitments are at Makita carbon brushes, Bosch brushes and DeWalt brushes, and they wear on sanders much like they wear on every other brush motor.