[lcuff]

I did a lot of the work in my 40 year software career as an individual, which meant it was on me to estimate the time of the task. My first estimate was almost always an "If nothing goes wrong" estimate. I would attempt to make a more accurate estimate by asking myself "is there a 50% chance I could finish early?". I considered that a 'true' estimate, and could rarely bring myself to offer that estimate 'up the chain' (I'm a wimp ...). When I hear "it's going to be tight for Q2", in the contexts I worked in, that meant "there's no hope". None of this invalidates the notion of a carefulness knob, but I do kinda laugh at the tenor of the imagined conversations that attribute a lot more accuracy to the original estimate that I ever found in reality in my career. Retired 5 years now, maybe some magic has happened while I wasn't looking.

[TylerE]

More than once I've used the xkcd method (Pull a gut number out of thin air, then double the numerator and increment the unit e.g. 1 hour -> 2 days, 3 weeks -> 6 months). When dealing with certain customers this has proven disappointingly realistic.