I am using Outlook to manage my calendar and tasks (for the most part as described by DA). However, one question I have is - how do I know if I genuinely have too much on my plate or whether it just looks like a lot because I have say 50 x 10 min actions on my list as opposed to 5 x 100 min actions on my list. In the context of a week or a month is there a way in GTD in which we can monitor the total time committed for a set of actions or a project and use this to monitor whether we can accept new activities or not and whether we are likely to meet existing committments or not.
On a simple level I was thinking of just adding a parenthesis to my task subject line to denote approx how many mins I think I need to complete the action... e.g.
A- Email ABC re: xyx 
would mean 10 mins to email someone.
Then if I have a short amount of time I can easily pick out the tasks that will fit in the allocated time.
But on the project level - how do we do this?
Does anyone else do this and if so - what do you do?