Apart from the obvious, buying a spare from your favourite supplier ( I’d get a lever and perch ), you could do what most off roaders do and not tighten the handlebar perch up too tight. Not loose so it rotates freely obviously, but just nipped up so in a spill the lever will turn on the bars.
Also, file a groove into the back of the lever closer to the open end, so if it does break, it brakes on the weakened line you have created….that way you can still use the lever until you get home to replace it.
Also, file a groove into the back of the lever closer to the open end, so if it does break, it brakes on the weakened line you have created….that way you can still use the lever until you get home to replace it.