Stacking is a term used to describe the length of pants. Stacked pants are long enough to sit on the shoes with some gathering to create a bend in the fabric. The stacked sweatpants and stacked denim jeans take this trend to the extreme with extra long inseams to create a lot of bunching above the shoes.
Rolling is what most people mean when they say they are "cuffing their jeans." A rolled hem is usually turned up twice at the maximum because otherwise, the roll can look too bulky. Stacked jeggings and other types of stacked pants mean the fabric is bunching up above the shoes. While this was once seen as a lazy trend, the fashion and music industries have made the look very fashion-forward. In order to stack skinny jeans, the inseam must be on the longer side, allowing the wearer to scrunch up excess fabric above the shoes. This looks best with high-ankle booties or high -op sneakers. Additionally, stacked jeans should always be pre-washed to avoid having any indigo dye from the jeans rub off on the shoes.
There are a few benefits to stacked pants. From an aesthetic perspective, stacked joggers break up the flow from the pants to the shoes. For people with really long legs, this can balance out the proportions of an outfit. This trend also shows off more of the shoes worn. Plus, by stacking pants, people can avoid paying a tailor to hem their pants, while also following a fun trend.