Get an emergency tire boot in case the sidewall of a tire goes out. In over thirty years of hard cycling, i've only had one sidewall blow, but that's what this forum is all about, being prepared. I don't carry chain links with me anymore, having never needed them. I use to carry a Topeak multitool, but found i only needed two allen wrenches, took off the chain tool to keep, chucked the rest, and carry a leatherman wave. Also, definitely get the duct tape. I carry three CO2 cartridges, better to have too much.