Have you actually had a look at the shoes? There's no noticeable difference in performance, sound, feel when the friction material is completely worn away, and the drums are very tough but will get scored eventually if it's just metal to metal.
Happened to my Huskys and one of my Hondas (so far), but I really give them a workout with line and metal blades, tackling rough brush and attack ~ 5 cm saplings with a vengeance. And wear down blades on rocks, and cutting weeds down to ground level or below.
Toughest blades I've found are Stihl's BrushCut which fit the Hondas. I sharpen them after every use, they work best when very sharp, but of course they shrink in diameter fairly rapidly - I consider them as consumables.
Have a look on eBay, there's several versions of aftermarket b/c shoes and drums for the different brands, it's not just me wearing them out
For Hondas there's aftermarket Heavy Duty shoes available, that's what I've bought.
Easy to check the wear, just undo the screws holding the housing to the motor.