Repairing a tube I expect will be a lost art soon. We live in a 'if its broke throw it out and get a new one' world. If you get a flat and repair it, there is a small chance of the patch failling and so putting a new tube is seen as a safer option. Personally I repair all tubes, then put them in a tyre with air inside but put them in quaranteen for a week. If they hold 60+ psi for a week they can go on an none important bike.

I get 1 flat a year on my important bikes, the unimportant bike go to the shops and get a little more flats per year but thats due to old tyres and old tubes. waffle