I've done a LOT of sporadic rowing over the years (without any commitment to keeping track), then I discovered committed rowing improved my blood glucose... and that LOTS of rowing VASTLY improved my diabetes—to where my daily numbers are usually in the "healthy/normal" range (>110) and steady throughout the day. My endocrinologist has reduced my insulin dosage twice in the past year. It's my dream to someday row myself off ALL diabetic medications. I found that logging online caused me to row MUCH more consistently (my kids say constantly). I can think of worse (much) habits and obsessions. I've also lost a little over 20 pounds since I started rowing hard and consistently last July... nearly impossible to do while taking insulin.
I'm usually on 'das boot' between 5 and 6 am, "resting" between pieces working out with weights, doing housework, and/or reading until 9 or 10. In the evening, I watch sports (football and college basketball mostly) while I row. The final two minutes of a pro football game can last over 20 minutes on 'das boot!' I can go a whole college game, but have yet to outlast a pro football game. Maybe next season. A side effect has been that I don't really like watching those sports without rowing anymore, which is a double benefit—exercise AND not munching junk food while growing roots into my easy chair.