I like Jason Fried’s idea of “doing something later” in a project in his latest post:

When you work on really long projects — say 3, 6, 9 month projects — or projects that don’t have any end in sight, “we can do that later” typically means you’ll get to it eventually, as part of the current project.

[…]

But, when you work in six week cycles, or relatively short time frames, later means something else entirely. There’s no time for later. It’s now or not. Later doesn’t mean we’ll get to it at the end of this cycle. It means we’ll drop it.

This is exactly how I treat my “later queue” as well in my various ventures. We often have a “Someday” list that is more of a punch list of ideas, but not a work queue. If something is important, it will come back up. If we don’t have time for an idea now, we skip it and wait for it to come up again. Keeping our task lists small and focused is the goal.