There are many different ways to think about this.
On the one hand, if there is a specific hotel you want...book now. The last thing anyone needs is to have their "destination hotel" turn up full when they've already got plane tickets.
On the other hand, DavidO has been able to leverage last minute bookings for us at some truly great hotels. If they still have the space a week out, they are more inclined to upgrade, etc.