Yeah, it won't work without a stable team. And that may be okay in a true agile environment but I've always had a manager who wants some type of estimate/high

Yeah, it won't work without a stable team. And that may be okay in a true agile environment but I've always had a manager who wants some type of estimate/high level schedule. We do T-shirt sizes mapped to numbers, because recording effort in numbers lets you get an avg etc...