This was the first time my new bike has been punctured since I bought it  five months odd ago. It's quite commonplace for the tyre to be punctured and get flat from time to time. It's unpredictable. I'm always watchful on my way when cycling to avoid dangerous things that can prick the tyres. If I had kept away from the doubtful rubbish with a cigarette end dumped on the path, the front tyre would not have caught the screw. Luckily I found the tyre flat just before I left the street behind. So I could go back to the repairer very soon. If getting halfway towards school, I would be in trouble.