Check your patch kits

I got a flat on a ride a few weeks ago.  No big deal as I carry a patch kit and pump.  However, when I pulled out the rubber cement vulcanizing fluid* from the patch kit it was like it had evaporated - there was nothing in the tube - even though I had never used it before.  It must have dried out or leaked over time.  Good thing I had a spare tube as well otherwise I would have had to make a pleading phone call.

Awhile later, I went to patch up the tube.  I pulled out another patch kit and it was the same situation - the  rubber cement vulcanizing fluid was dried out, as well as the patches themselves were not very pliable.

As far as I can tell, there's no "best used before" date on these kits.  You might want to write the purchase date on them and then toss them after some time (maybe a year? 6 months?  who knows).

* Note that "rubber cement" is not the same thing as "vulcanizing" fluid.  Vulcanization means that the two layers of rubber are actually chemically bonded.  Regular rubber cement (depending on the formula) may simply stick the two layers together without vulcanizing them.