Our recommendation has always been to weigh yourself every day, at the same time each day. For many people that is the right after you wake up and used the rest room before you've had any food or drink.
However, sometimes, the scale starts to act "weird" - we get the exact same reading 3+ days in a row, or large (3+ pound jumps) up or down that don't make sense.
While some of the readings may be accurate, lets rule out its the scale by checking the following:
Make sure you are using a brand of scale that is recognized by third-parties to be accurate. The scale we recommend is the EatSmart CalPal Digitial Bathroom Scale.
If its been awhile since you changed the batteries, go ahead and change them to fresh ones. Old batteries can cause some weird behavior in scales. Re-calibrate the scale - for most digital scales, including the one we recommend above, you do this by standing on the scale for a couple of seconds and then stepping all the way off and letting the display reset to zero. Then stand back on and re-weigh. You need to do this when you change the batteries, or anytime the scale has been physically moved. Try and keep the scale flat and in the same spot if possible so you don't have to calibrate it everyday. If you have a different model of scale, you'll need to double check the instruction manual on how to calibrate.
If you've tried all of the above, and the scale readings still seem a bit odd, reach out to your coach and get some feedback. Sometimes its the food choices we eat causing water retention or diuretics or even inflammation from a tough workout.