Twice the time from start to 50% complete.
HA. Yeah right. It never works like that. Not even close.
I just read a really great (buy quite long) post about estimates and why we suck at them.
I will TLDR; this into a few bullet points here, but i really think you should read the whole thing.
- Our brain has 2 ways to estimate, quick gut feel based on patterns/experience and methodical expensive based on slow thinking
- Both suck
- Big estimates (e.g. 2 weeks, 2 months) have almost no chance of being right
- Small estimates (8 hours or less) have a better chance // I’ve seen this first hand.
- Small estimates let you get fast feedback on how bad you are
- You WILL still get your small estimates wrong
- But, short sprints place a hard limit on the cost of a horrifically bad estimate
- Agile rocks