Had my first tubeless fail today - puncture that wouldn't seal. After the learning curve that I went through with installing the tires, though, the roadside service was straightforward and no worse than changing a tube in a tubed system. Turns out that the failure was totally my fault - the sealant was completely dry and boogered. The not 'ha-ha' kind of funny thing is that I was thinking about the sealant and how many more miles I should try to squeeze out of the rear tire about 45 minutes earlier in the ride.