[nikolaj]

same experience level, similar formula. Take your gut estimate, double it, double that new value, then add another "increment".

e.g. say you think it will take a day, so 2 days, 4 days, add another day, likely estimate is 5 days.

My pet theory is that when we estimate, we typically think of how long it will take to figure out a working solution to the problem, but forget about how long it takes to debug it, add tests, rework for changed requirements and unexpected nuances, and then roll it out and do any training, etc.