I weigh pretty much every day, but I change my forum stats only once per week (if there's a change ). I do it, like most people it seems, first thing in the morning after a full night's sleep, after going p, naked, before eating or drinking anything.

Do NOT weigh yourself right before TOM It's depressing for me and I just skip that week and get a nice surprise the next week

As for measuring, I do that when I'm feeling skinnier and/or every couple of weeks. My inches lost seem to keep pace with the pounds lost (ie I've lost over 20 inches and 26 lbs so far!).