Over 25yrs or so of outdoor activities, I've rarely had to effect any repairs, and what has needed to be repaired has been easily done in the field.
I bushwalk, fly-fish, packraft, ski tour, and sea kayak.
To date , All bushwking repairs have been easily with a needle a thread.
Fly fishing repairs have extended me to using braided nylon and super glue when my fly line breaks, and aqua seal for wader repairs.
Packrafting hasn't really caused me anymore issue to date, other than a lost valve cap, which was resolved with a plastic bottle we had.
Ski touring , I've had one catastrophic binding failure which required. Walk back to home. would have been fixed by carrying epoxy glue , and a screw driver.
Sea-kaykng.........not had my Yeats, but wouldob carry some epoxy and fiberglass ape if on. Longer trip.
At the end of the day, repair kits can be kept quite simple.
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