I'm on the pill so I kinda forget when TOM is due... I realize it when I see a sudden spike in my weight (I weigh daily) and I can't explain it away. I think it's good to see up and down blips. Helps me understand your body better and not get so frustrated throughout the process. I also like the sudden drop in weight following TOM. Well, in my case I only go up 2-3 lbs, so it's not THAT big a drop, but still, makes me happy.
