When buying a new drysuit or when changing the seals before diving, you always have to cut the seals.
The seals on the arms and neck are present with drysuits to prevent the entry of water into the suit.
It is important when cutting, that you use a sharp pair of scissors. Blunt scissors tend to leave a frayed cut. These frayed sides are potential weak points where the seals could crack.
So if you have previously cut paper with scissors, these are not good enough for the cuffs, since blades can get blunt very quickly.