Workflowy cuts my packing time in half, or close to. It's amazing.
With my usual travel list(s), I get into an obsessive-compulsive scanning doom loop.
I put something in my bag and cross it off my list.
Then I put something else in my bag and cross that off my list.
Unfortunately, crossed-off does not mean invisible, so every time I check my list to see what to pack next, I end up rereading the whole thing, or at least re-scanning the whole thing; plus I start to experience doubt.
Did I really pack the long cord for the iPad? Sure I crossed it off the list, but did I put it in my bag?
(Same problem with recipes, btw.)
With Workflowy, when you cross something off the list it disappears (if you want it to).
So the list gets smaller and smaller, and there's never anything to scan other than items you have definitely not packed. There's no re-scanning, and there's (almost) no checking or re-checking. Out of sight, out of mind.
When you want to restore the list, you just Un-cross all the crossed-off items et voilà! List restored.