>>1223039If you are getting sixth puncture that day, you'll understand.
That being said - every puncture leaves an entry wound in the tyre, which is, usually, on the running surface and an unprotected by the tyre itsself. Having a patch below that hole reinforces the tyre, making it less likely to get punctured again by debris entering the cut.
Essentially, you should never replace tubes unless really necessary and should make sure that patches line up with holes that made them.
