I feel like I should have some already.

Last night I discovered my current go-to messenger bag - the one I got working for Scholastic, which remains the best summer job I've ever had - broke a seam. It's got a small, one-inch rip at the bottom, not enough to compromise structural integrity as is but plenty to cause major damage if I keep using it. At first I was pretty put out, as this bag's seen me through a couple other jobs and a lot of travel, and I don't want to go to the trouble of replacing it.

I thought I could fix it, with heavy-duty glue and-or duct tape, either or both of which I'd have to go out and buy.

Then I remembered I'm very much a packrat, and dug through my closet, and came up with another messenger bag buried at the bottom of a box. Perfectly serviceable for work, and more than capable of holding on long enough for me to go out and buy some duct tape.