Trisk, I kind of do what you describe, because I know how my body works, after all of these years. I weigh in the AM, right when I get up. I know if I weigh myself even right after I've eaten breakfast or, ah spent time in the bathroom, I will be 1-2 lbs. up and that is normal for me. I do look for patterns, and this is why I decided to start doing something differently, as the pattern I saw wasn't good! I don't want to gain 5 lbs. every winter.
I do weigh myself everyday, because when I don't, it seems to get away from me. I know that it will be higher after the weekend, due to either going out, or a long, hard ride/ski, or both.
OK, going out to run/walk. Three types of exercise in a day is a lot for me, but the first 2 were not really strenuous.