Due dates vs calendar / regular appointments
Hi. Just starting out on using GTD properly (and using Things for Mac and iPhone to help with that).
Couple of things where I'm not quite clear on the best way to handle them:
Due dates vs calendar entries. Things offers due dates, but the GTD book doesn't seem to mention due dates at all, and suggests a calendar for completing tasks by essential deadlines. My issue with that (for home, not work) is that the calendar then becomes quite restricted - a lot of what I want to get done at home has no essential deadline, but I need some way of committing myself to making progress. Due dates feel like they could help with that, but not sure.
Which is sort of related to another question - how best can I manage regular, non-essential commitments? Best example would be something like exercising - putting it in a calendar might help me commit to that, but it isn't absolutely essential I exercise at the given time - and I remember DA's point about the calendar being sacred territory for essential things. Either way, I'm by nature not great at getting stuff done, so I'd really like to use GTD to get a few things in order.
Any advice much appreciated!