you went 2 years w/o a flat?? congrats.
I always replace w/a new tube. They are a consumable item and usually > $10. gotta pay to play.
when I ride I bring 1 new tube and a patch kit. it hasnt happened yet but if I got 2 flats on the same ride I could repair it.
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2010 Kestrel RT900SL, 800k carbon, chorus/record, speedplay, zonda
2000 litespeed Unicoi Ti, XTR,XT, Campy crank, time atac, carbon forks