Do you ever draw the same subject over and over? I take my kids to a swim class pretty much every weekend, and I inevitably end up sitting in about the same spot ( to be near where they are) and sketch for about the same amount of time- 20 to 25 minutes. So now I have a whole bunch of sketches titled "Weekend Swim Class at Almaden Valley Athletic Club, San Jose"!
These 3 sketches are in chronological order, and while I sometimes think "not another pool sketch!" I think it's interesting to know a subject well from drawing it over and over- and to find interesting ways to look at the same scene.