This may be an answer to anyone getting broken speedos/odos perhaps a "little too often", note, this is a speculation but I think it has value,
makes some sense to me.

Speedo breaks, get another, that one breaks, get another, etc. So,whats going on? This of course is an opinion but makes sense I think. Speedos are getting older and older. The little gears inside getting more and more brittle. The shafts they turn/rotate on getting gummy-er. Step on the gas hard, then wonder why the little brittle gear goes "byebye"?

One solution, drive easier. Next, take that next odo, clean it thoroughly and any and all "shafts" the gears turn on. Then clean and lubricate as many little gears as possible. After having done so, drive easier.