i thought this was o topic about disc pads then,
rim brakes dont have a bed in like discs do, all you need to do is line them up correctly so they hit the rim dead on flat.
bedding is the pads is basicly wearing down the pad surface so all the pad touches the breaking suface all at once. most rim brakes will do this at the 1st time the brake is applyed (its all down to getting the angle, height and twist adjustments all spot on)keep a good fresh grind on the rim if you use grinding.
disc brakes ware the disc much differently to rims, the outer edges of the disc are coller to the centre and ware out at different rates, older discs will take longer to bed in to newer discs. most disc brakes will take from new 3-4 aplacations of the brake, older discs will take anything upto 3-4 times more aplacations.
to check if your disc is worn check the centre of the surface is not concave (thiner in the centre and thicker on the outside edge and inside edge.
any how you will feel your brake is not working as well as expected. common problems are:
incorectly adjusted pad to rim contact. ( be aware to adjust the pad contact winder all the way in before adjusting the 4 point mounts)
old used unsharp grind, check with your finger by rubbing the rim, a good grind will feel sharp and a bad one you will be able to push your finger hard on the rim and slide your finger without tearing or sort of fileing your finger.
and the last would be a brake in need of fresh oil or more oil. old oil will be unclear and black in colour, it will slowly cause the brakes to seaze and fail. low oil will make the brake feel spongy and the lever will hit the bar before stopping the wheel.if you wind out the adjuster and tap the lever you should see the pads move even on the slightest lever movement.