Black pants hide any Contact, and tucking the right leg cuff in my socks* keeps it out of the potential chewing by the chainring teeth.

* trouser bands and clips can do that too ..

I have disc chainguards added outside the big chainrings on several bikes . they are aluminum .

When the included plastic ones in No 20 are hard to replace when you brak them . as they are part of the crankset in the package.