Marcelo advocates specialized sparring for garnering improvement: Minimize your propensity for making mistakes by varying up your training partners when possible. Get out of your comfort zone so that you don't develop bad habits or big holes in your game. Short rounds of specific training on a particular position is one way to help isolate a problem area, and it can help you find weaknesses that come from complacent or predictable patterns. It is better to find your mistakes before a competition rather than the day of; everyone makes mistakes, so it is best to learn how to avoid or conceal them as best as possible beforehand.