How do you choose a multitool when there are more than 1000 different ones available at the big online retailers? Depends on how long, where and which discipline you ride.
First of all, lets be clear here. Most tools will work for most situations, so you won’t need to buy multiple tools. As long as you choose one with the most used tools you’ll be able to at least limp back home in most situations.
Get a tool that fits your bike
Make sure to check if your bike uses Talks keys on it and find a tool that offers those.
Some things are more likely to happen while riding a mountainbike as opposed to a road bike. rocks are more likely to fly up and cause damage. Spokes are more likely to be shaken loose. Many tools come without a chainbreaker tool, which I suggest you stay away from. I have used mine 4 times in the last 4 years. Which isn’t much, but boy has it saved me some long long walks home.
You don’t need as many tools on the road. You are less likely to have a spoke work it’s way loose if you stay on top of your maintenance. But since most multitools are quite small anyway I would suggest you get one that fits both disciplines if you ride a mountainbike as well.
Fitting a tire lever in your pack or on your multitool can be a great idea, since road tires can be hard to get off the rim.
The longer you ride the more tools you should carry. Maybe you would even want better tools if you are touring for multiple days and your progress depends on your bike working.