If you don't keep a training log, you should. I've been keeping one with my workouts, submissions, sweeps, things I've been submitted with, and strength and conditioning workouts for the past 2 years (almost).
At any rate, you'll notice over time that trends or patterns emerge. You'll also have statistical date to draw conclusions about the progress/evolution of your game rather than generalizations we tend to make about ourselves when sitting around playing Battlefield Bad Company or playing beer pong with training partners.
You might think you're the armbar King or the triangle Jedi master, but in reality, you've only submitted white belts or the occasional blue belt for the past 3 weeks with your submission of choice. Obviously, there would then be work to be done in addressing your set-up, what positions in which you then secure the triangle etc.
Perhaps you've decided that getting off your back is your new mission in life (as it was mine after my 3rd MMA fight). I've spent virtually every roll session starting off my back for the past year and 3 months. At this point, it takes a long-time purple belt to keep me there. I'm not saying this b/c I'm the BJJ wizard, but even in rolling 100% I've seen progress and experience at escaping this position and getting to top position. As a result, maintaining top position whilst looking to submit is my new mission.
Writing down on a daily basis one submission or one position, or one sweep which you will try on every training partner has the added bonus of holding us accountable.
It also helps organize training for upcoming tournaments and addressing how much BJJ you actually know and/or attempt/do in training. Seeing that you are 3 weeks out from the next Submission Only or In House tournament might convince you to stay on the mat for one last roll or three at the end of the week. It might convince you to get up early and make it to Open mat on time or skip the fifth beer the night before.
You might think your back escapes are "good enough"....but if you decide to start with your back taken by every guy in the room, you may find that it bears a bit more attention.
At any rate, happy trainingz.