[P5fRxh5kUvp2th]

estimate both a time and a confidence (or fitness).

2 weeks with 9/10 fitness is a very different estimate from 2 weeks and a 6/10 fitness. The latter should result in more discussion so those you're giving the estimate to can better understand how likely you are to miss that estimate and what they can do to facilitate a better estimate. "Give me 2 days to investigate this 1 thing that's a total unknown, I can probably give you a better estimate afterwards".

The problem is very few people on either side of that table ever want to do this.