It's more like "the last time I did a case like this it took around 3 weeks to close the case, so 3 weeks this time. Maybe a little less because there's less e

It's more like "the last time I did a case like this it took around 3 weeks to close the case, so 3 weeks this time. Maybe a little less because there's less experimenting.". Basing it on past experience like that automatically takes into account (average amount of) meetings, waiting on others for code reviews, etc.