Adjustable laced sides on a vest allow you to expand the vest to fit over a jacket or tighten it down if you're just wearing a t-shirt. The sides are secured by a rawhide thong, which can be easily replaced. The eyelets are set in a double thickness of leather and reinforced by stainless steel gromets.
Adjustable snap sides are quicker to adjust, but only tighten the waist of the vest and are limited in the range of adjustment as the snaps can only be undone, on the first snap or on the second snap.