Always have spare ss sweeps. Had purchased at least a dozen grills the past year just for the ss sweeps and burners. Swapped the parts, sometimes with new aluminized version, and turn around and flipped it. Prior to that i was replacing my sweeps every year. The ss sweeps should last as long as the kettle. Seems like they were standard between 2001-2010 on the performers, otp and otg kettles. The later ssp and earlier gen3 came with ss sweeps and burners.
Don't have any of the new sweeps but if they are magnetic, then weber probably had transitioned to 430 ss. The older ones are likely the austenitic 304 variety. Except on the Summit gassers or probably WCG, weber currently uses 430 on most if not all of their products.
All it takes is 5-10 minutes to bring it back to tlife.