I think if you genuinely are travelling in the middle of nowhere, and can't rely on friends or a recovery service to get you home, then carrying a variety of common spares is prudent - regardless of the make and model of bike. I think the Himmie scores better here than most bikes since it's so basic and has so few electronic parts compared to most modern motorbikes. It can't fail if it doesn't exist!
I'm slowly building up a small cache of parts even though I'm rarely more than a day from home, but mostly so I don't have to wait for replacements if something does go.
WARNING! LONG POST WITH PERSONAL OPINIONS!
While I agree that for long or epic journeys it would be prudent to carry some primary spares, there are a number of RTW type journeys documented on the internet, and probably more not, where the issues we're discussing never materialized. Most of those travelers praising the reliability of their Himalayan, equaling or exceeding their previous bikes.
I think we all know that complaints and issues of products on given forums are extremely disproportionate to total ownership experience, evidence showing that most owners are more likely to take time out of their lives to complain about a product rather than praise it. The exception being enthusiasts or fanboys.
I've been on several motorcycle and a couple of tech product forums where it was common to see a new member pop up, ask for advice or voice a complaint with a problem they were experiencing, then disappear until the next problem. That's OK and normal for forums, being what many use forums for. That rarely holds true for owners with good ownership experiences. It's very unlikely an owner will join a forum to post a praise or recommendation for a product, usually due to their good experience not impacting their lives like a bad experience does. We all love to complain and tend to be more vocal and sharing when we're pissed off or disappointed in something than when we're pleased with it.
Then there are those of us that have a passion or serious interest in a product, join a forum to either or all, learn, share, assist and contribute to the overall knowledge and experience base of a product, often benefiting ourself as much as others. This type of owner, unless a fanboy, will usually share complaint as well as praise in deserved manner, sometimes with maybe a little bias

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Getting back to the original point, I do a lot of long distance or long duration camping on my bikes and over the many years I've come to embrace the adage "light is right". I try to carry only what's absolutely necessary. So rather than carry a lot of spares and given the questionable quality or durability of several Hima components, I prefer to replace them now with reliable or track proven components rather than deal with a potential failure on the trail. Never a guarantee I know but definitely lowering the likelihood of failure considerably. That's my preference and I know it doesn't work for everyone. I'm big on preventive maintenance over what I call reactive maintenance

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