[anon]

I use duration as a time estimate on how long certain projects will take me. I also use it to make sure my tasks are broken down enough, i.e. not into 4 hour or more chunks. I have a tendency to put projects vs. tasks on my "to do lists" and can never get started that way. I have a rule if something is over 30 minutes I need to break it down more during my weekly planning.

However, like a lot of features in omnifocus, don't feel like you "have to" use them just because they are there. You can waste a lot of time just "fiddling" with the system vs doing.