Does anyone know how to add a custom field to the task form to allow an estimate of time to complete the task. I want to start using Daylite as a time management tool and see how I go

Won't the Due Date work for that?

No the due date is when I promised to do it by - it may be in a weeks time but the task may only take a day. The thing about time management is that I might have 10 other task to do so it comes down to making the most a your work day to knock over the important tasks first. I know I can change the priority but my intention is to work out how much of my day will be taken up with completing tasks by the due date so that I can quote reasonable due dates in the future as well as scheduling meetings, site visits etc.