The manner in which clothes are manufactured these days is quite different from how things were done in the past. Back in the olden days, people made clothes according to their own specific body types, but their methods were really imprecise so while their clothes might have almost always fitted perfectly suffice it to say that they were limited in terms of comfort as well as quality. That resulted in standardized sizes being adopted after industrialization, and they can help you buy your appropriate clothes more easily at any given point in time.
A big part of the reason why that is the case has to do with the fact that these sizes tend to cover many if not most of the general sizes that people adhere to, but another thing that results as a consequence of this way of doing things is that people who are in between sizes can feel left out in some way, shape or form. If you want to buy Niyama Sol leggings but feel like none of their sizes fit you properly because some are a bit too small and others are a tad too big, you might feel like there is nothing that this brand actually has to offer you.
However, there is nothing wrong with sizing up your leggings if you are between sizes. This ensures that your leggings will more or less fit, and while they might be just barely too loose that’s better than them being on the tighter side of the divide because leggings that are too tight for you have a much higher chance of getting ripped while you are going about your daily routine.