This decision is a matter of personal preference. Most pros find that shoulders pads make the jersey fit awkwardly and cause it to bunch up, so they prefer not to wear them. In addition to being a personal preference and often an aesthetic choice, it's also a toughness thing.
One of the most protective lacrosse chest protectors is the Maverik Max which features removable bicep pads, a hard triangular chest plate and large non-adjustable shoulder caps.
Lacrosse chest pads are a vital part of protective gear, but they need to fit securely in order to protect you. How your shoulder pads fit is important, so make sure that your chest stays centered and high on your sternum and away from the armpit. The collar should be snug to your body without restriction, but not too tight that it digs in uncomfortably or limits your range of motion.
Lacrosse shoulder pads are similar to those in hockey. They are much lighter than football shoulder pads and therefore more comfortable for new players. They should fit comfortably, covering the shoulder and upper arm. While lacrosse specific shoulder pads are optimal, hockey shoulder pads work perfectly fine as well for newer players.
You can cut lacrosse shoulder pads, but it's not recommended. A lot of people cut shoulder pads because they want more mobility and flexibility but cutting the caps off of your shoulder pads can affect their level of protection and safety. It's an illegal equipment modification and could potentially get you into trouble with the referee or even suspended from games if done improperly.
When choosing a style of lacrosse shoulder pads, it is important to consider both the needs of the player and their skill level. Restricted movement caused by ill-fitting pads can result in injury and impact a player’s performance on the field. Regardless of which style you choose, players should look for shoulder pads that fit snug to the body without restricting movement, while offering ample padding in the sternum and collarbone areas.