Advice about babies comes with large error bounds. It’s reassuring, up to a point. “Oh, that? Anything between three times a day and once a month is normal, yes.” “Aha, right - OK: sometimes there are three of them.” That sort of thing.
Due to the “red book”, all parents know their child’s weight, and also know which percentile that puts the little blighter on.
Slightly worrying to hear, though, that a health worker told a friend of ours “mmm, well, 99th percentile is quite high. We only worry, though, when it goes above 100.”