What tools on a multi-tool do I actually need? I feel like there are almost as many bike multi-tools out there as there are bikers. In a single trip to REI, I found nine different bike tools each ranging from only four to over thirty individual tools! But how many of these tools do I actually need?

I feel like some of the tools included in these multi-tools aren't really ever going to be necessary in the middle of a ride, but are actually better suited for at-home repair.

So, what tools do you actually need to carry with you, that you might actually need while out riding, and what tools are you can safely leave at home?
Minimally, you want to be able to tighten all of the bolts on your bike (likely a few hex keys will do this) and an appropriate screwdriver for adjusting derailer &amp; brake pulls.  Separate from a multi-tool, a pair of tire levers are the other tool you should carry with you.

I would add a chain tool to the above list after being left in a state where I would have been much happier were I so equipped.  For that reason, I bought a Crank Brothers Multi Tool 17 which features the requisite hex keys, screwdrivers, and a chain tool, in package that is smaller &amp; lighter than most Leatherman tools.  Some of the hex key sizes don't fit anything on my bike, but it's nice to have a set that can help most other riders.