Every padel racket arrives with a grip on the handle. An overgrip is a second, thinner wrap that goes over it. The question of why is a reasonable one, and the answer is mostly about what happens to a grip over time.
The original grip is not meant to be replaced often
It is bonded to the handle and part of how the racket was built. Replacing it is a job. An overgrip is a strip of tape that goes on in a minute and comes off in seconds, and it is what takes the wear instead.
Grip is the cheapest thing to renew
An overgrip costs a fraction of a racket. A handle that has gone slick costs more in mishit shots than a fresh wrap costs to fit, and the racket underneath is not improving while it is being held badly.
It also changes the handle
An overgrip adds a small amount of thickness, which some players want and some do not. Wraps differ in that thickness and in surface: perforated ones move moisture away from the palm, tacky ones hold the hand more firmly, and dry ones aim at the opposite. This catalogue records what the maker published — usually the type and the pack size, sometimes nothing more.
Pack sizes
Overgrips are sold singly, in blisters of three, and in boxes and buckets of sixty or more. The bulk formats are how clubs and regular players buy, because the per-unit price falls sharply and sealed wraps keep.
Related but different things
Several products sit near overgrips without being one. Grip gels and sprays treat the hand rather than the handle. A towel deals with the same problem in another way. A vibration damper sits in the frame and has nothing to do with grip at all, despite often being sold on the same shelf.
How often to change one
There is no schedule that fits everyone, because it depends on how much a hand sweats and how often the racket is played. The useful signal is not the calendar but the feel: a wrap that has gone slick or hard has stopped doing its job, and one that has started to unwind at the butt end will not come back. A player who trains several times a week will get through them far faster than one who plays on Sundays.
Thickness and handle size
Padel handles come in a narrow range of sizes, and a wrap adds a millimetre or so of diameter. For a hand between sizes that is useful; for one already at the limit of a comfortable grip it is worth knowing before buying a thick wrap in bulk. Two thin wraps and one thick one are not the same thing.
Perforated, tacky, dry
The three broad families solve the same problem differently. Perforated wraps move moisture off the palm through holes in the tape. Tacky wraps hold the hand more firmly and are usually preferred in dry conditions. Dry or absorbent wraps aim at a matte, non-sticky surface. Which suits is a matter of hand and climate rather than quality, and this catalogue records the type as published without preferring one.