"Who is going to do it?" is always my first question whenever I am asked to estimate a piece of work. PMs/EMs are usually taken aback by the response, as if we are all supposed to pretend that all dev "resources" are equal. Yet reality doesn't fit into neat planning spreadsheets or burndown graphs, so often gets ignored.
Unfortunately we were never allowed to do that, because of Scrum, and were only able to do it on the low down for a short time until management cracked down on it and enforced "anyone who happens to be free works on whatever is on top of the backlog".