Mathematicians have since the 16th century tried to calculate randomness and predict statistically when events occur favourably or unfavourably. I wonder if they have come out for a formula for bike punctures.
My son has been riding the XO5 faithfully for 16 months with no incident and in a span of a week, had 2 flat tires, both front. Actually, these are the first occurences of flats on the XO5's 17 year life span.
The first flat was unexplained and mysterious but the second one, Jem carelessly ran over some thorny bush on his way back from school. Guilty as charged! He had to push his bike all the way home, twice. This resulted in me using a tweezer to pull out 8 small but nasty spikes. I also learned that a 700c tube here in Australia costs US$8 compared to Singapore at US$4.5!
So whatever probability theory can tell you about your chances of having a flat, one way of making 100% sure that you don't get stranded is to carry at least one spare tube, tire levers and a pump.
ps 1: My friend Mike Khor of Wheelsopher went on a long ride recently on his Surly in Malaysia and had 3 punctures in one day! No need for applied probability theory here as it was due to a very explanable "technical failure".
ps2: 1 June - Front tire punctured again!!! Arrgh. Closer inspection revealed a pinched flat, careless of me during installation. Please remember to pump the tube a little when fitting into tire/rim. Hope this 3rd tube will last for some time. Silly me!
ps3: 17 June - This time the rear tire had a thorn go through it. Another new tube needed in such a short span of time. When it rains, it pours! I now have 3 tubes to patch. Sigh...