You want to improve. You need to improve. Progression is the driving force behind your passion and love of Jiu Jitsu. But…how do you know if you have improved? This is a notoriously hard problem. As you improve, so do all of your training partners. There are no metrics to measure your skills. It's an experience. It's a quality. It’s an art!
To measure your progress requires a recording of your experience. By recording, I mean write it down. As an example, what are you good at? Closed guard? Good. Let's use that as an example.
Write down all the concepts and techniques you know about closed guard. What is your game? What is your focus? Brain dump this onto paper, and then organize it the best you can. Now, keep that somewhere safe. In a drawer. In your phone. On your spouse's phone. Whatever.
There is no right time, but time is important. Let it pass. A month. 6 months. A year. Then go back and read what you wrote.
What do you think? Does it feel like you have grown? If you did this exercise again, what would your closed guard brainstorm look like? This is the best way to measure your progress. You can’t assess yourself against your partners. They are growing too, and all at different rates. You need to assess yourself against yourself to measure progress.