My boys were and still are weighed often, but they've always been classified as 'under-weight' (not that I think they are...) so they like to keep a close eye on them.
Sorry I can't really help here. I hope someone can.
In the early days I only weighed DD when she had her checks with the MCHN, and since then when I happen to be at the GPs office... roughly every couple of months. The best advice the MCHN gave me was "Look at your baby." Sounds so simple and logical but to a first time Mummy worried about bf supply it was a revelation. If you can see that bub is healthy and there are plenty of wet and poopy nappies, I wouldn't be too worried about a number on a scale.
All babies are different and everything is relative - I've had people say that DD is HUUUUGE and also TIIIIIIIINY - of course, in comparison to their bubs. I'd say only weigh as often as you feel necessary, but don't stress yourself out over it. A friend of mine who is a highly anxious type limited herself to once every two weeks, otherwise she would have sent herself (and the nice ladies at the pharmacy) around the bend.
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