You really just need to figure out what issues you've had in the past while on the road with your bike and what you'll likely have happen in the future. As well whether you know how to fix the stuff that you'd use those tools for. A couple hex keys, tire lever, spare tube and inflator are about all I've used for the last six years. I've trimmed some stuff out of my kit that I no longer carry.

If you are riding far from home, you probably need to be better stocked for tools than I am for my rides. Even my 60 plus mile routes are never farther from the house than a 20 minute drive in a car if I'm so broke down that I need someone to come get me.