Opinions on the little plastic disk that goes behind your cassette? I know some people who vehemently disagree with having these on a bike, but it just seems like a cheap bit of insurance to prevent a derailleur that gets banged out of alignment from jamming into and ruining your rear wheel to me. No?
pie plate screams "I don't take care of my bicycle"
If your derailluer is properly adjusted you won't need one to prevent yourself from shifting into your wheel
If your hanger or cage get slightly bent such that you can still ride and may shift into the wheel, you will notice it and take care of it before breaking anything
If your derailleur gets ripped off your bicycle, hanger gets bent 90 deg., or some other such disaster, your pie plate will still not stop bad things from happening to your wheel because it's a shitty little piece of plastic that will get fucked at the slightest touch
note literally zero pro mountain bikers (i.e. people who hit smash derailleurs for dollars) ride with one. If they don't need it, neither do a bunch of freds who won't get any more rad than riding up their gravel driveway.