Spend time to fully estimate each task in each feature point in hours and double it of course. Now increase the unit of time by one: 3 hours = 6 days, 2 days =

Spend time to fully estimate each task in each feature point in hours and double it of course. Now increase the unit of time by one: 3 hours = 6 days, 2 days = 4 weeks, 4 weeks = 8 months.