Distinguish 'start' from 'due' date for a task
Many tasks need to be addressed over a range of dates. If it's a big task, the 'due' date could be days or weeks later than the start date. Currently to model this in checkvist, uses can only try a kludge-by-convention (for example use a 'start this' subtask).
Also please take a look at this issue, maybe this is what you want to see implemented instead: https://checkvist.uservoice.com/forums/2121/suggestions/399064
I want to mark a time to Start working on a task and get notified when it's time to start.