The lanes in this part of the world are periodically littered with hedge trimmings which are lethal to bicycle tyres. If you have to put a new tube in every time it can get damned expensive. It's pretty easy to patch a big fat MTB tube but I've always found it very difficult to get a good seal on 700 x 23c tubes - the best I've managed is to reduce the flow to the status of a 'slow' puncture - one that'll need topping up once a day. I think it's the combination of the small tube circumference and high pressures (100 psi +). I used one of these yesterday and immediately noticed a difference - the square patch was a much better fit across the tube and the seal was good even though the puncture was near the tube seam. The tyre was still rock solid this morning and I'm in no hurry to stick a new tube in.