Hey!
Measurements, like the scale readings, are only numbers--but my guess is that either you are retaining water when you get a higher measurement, or you are measuring in a slightly different place or with the tape at a small angle. How much difference are we talking about?
It's best, I think, not to take measurements any more frequently than once a month.
I had someone at Curves measure my bustline and get 2 inches larger than the previous month. One of the measurements was therefore off, because at my age, I'm not getting bigger there!
Jay