Try to do my own maintenance, which can be a pain at times, but this thing makes it a lot easier when dealing with chains. Still need a chain breaker to get the right length, but then installingremoving is a breeze.
When I was initially building up my new bike, I mainly just transferred a lot of the components from my old frame to the new one, and was figuring I could use the KMC chain it had as well. I ended up getting some used components from my cousin - which were still an upgrade for me - including a barely-used Ultegra chain. Though I'm sure neither brand recommends it, I decided to use the Missing Link on the Ultegra chain, and it works great! Have put nearly 1,000 miles on it and no issues.
As a bonus, the openings on the MIssing Link make it a nice visual reference for lubing your chain, to know that you've hit every link!
Inexpensive and reusable, I install these on all my chains so that I can break them and reattach them for cleaning and other drive train maintenance. Years ago, I also purchased the Park tool that makes removing the link a one-second process, although you could also make a small needle nose plier work as a removal tool. No tools needed to reattach. Simple and practical, these make removing and re-installation of drive chains an easy-peasy process. If you care about having a ridiculously clean drivetrain, you need these on all your chains.
A broken chain link on the trail is rare, but it happens from time to time. One of these in your kit is a perfect companion to your multi-tool - - you can fix your chain without having to compromise its length. And it's a LOT easier than trying to drive a rivet back into a link!