Ive ended a tour with over ten patches on a tube, without throwing it out. And ive had two or three punctures on a bad day, so would have been up the creek without a good patch kit.

If nothing else a press on patch kit takes up so little space sometimes I cant find it in my saddle bag on my road bike without digging.

Most of my tubes were picked up from other people on group rides who cant be bothered to patch. If you do choose to buy a new tube every time, at least offer your old one to the shop where you buy the replacement.