I don't keep track of how often I sew on my calendar, but I do keep track of how many quilts I have made so far. My sister, who taught me to quilt 4 years ago, suggested this, as she wishes she knew how many quilts she has made. Every time I finish a quilt, I mark it on my calendar, changing the number so I know my current count.
I like knowing how many quilts I have made, though I do break it down into quilts, mini-quilts, and "cat-sized quilts. It makes me feel good, knowing how many I have made.
I basically sew at least something every day, so marking that info wouldn't be as interesting to me.
Dina