Which Chain? (Chains / Size / Width / Wear)

Not had a chain break on me yet in many years of cycling. I did have my back axle snap two days ago though. Luckily I could roll some of the distance home as it was a quick release wheel and the skewer meant it still held in place. Knackered the skewer too though but at least I got home without a long walk. If it had been a solid axle I'd have been pushing it home and would have probably lost all the bearings etc.

You can't carry everything with you for every possible repair but if you can get a multi tool with a chain breaker in it then it can't hurt to carry a couple of links. Especially if yo uhave them left over from fitting the chain when you first put it on.

What make / model tool is the one pictured?

Rear axle snapping usually only occurs on cheap hubs because the bearings are placed just on either side of the hubshell leaving a massive overhang of unsupported axle inside the freewheel/cassette.

Shimano hubs have bearings right at the edge of the freehub so it is supported at its two ends of the axle making snapping very very unlikely. Just a tip for the future.