[justherefortart]

I make my best guess and quadruple it. That tends to be the most accurate I get.

I underestimate everything and also forget interruptions, new "on fire" issues, life events (turkey day, etc) and everything else.

So instead of worrying about all the stuff I'm missing, I just give my best guess and say it's that. A guess. If you want to hold me to an estimate, I need weeks of planning to get back to you. In that time I can do the missing BA work, mock up what needs to be done and get a better estimate, which I'll still quadruple.

[ghaff]

An engineering manager I used to work with would drive me crazy. He had this "methodology" he referred to as a 90% schedule but it was a 90% confidence schedule only in the sense of no one ever getting sick for a couple of days, tests not failing, no hardware being defective, etc. etc. It won't come as a surprise that this schedule was basically never met.