-
What if all your spares split down the arse? What then?
Edit: I'm just joking really. But bag/shoe/clothing/tent repairs could be important on a ride one day. You could probably stitch together a tyre that's totally shredded or a sew up a wound in the worst case scenario. Worthwhile skill and a needle and thread probably weighs only 5 g if that. You're right though, poking a needle through a bit of fabric isn't hard and you don't really need to learn anything to do it.
Sewing lycra? Can that actually be done?
Pushing a needle and thread repeatedly through fabric is probably not going to trouble me on the 'difficult skills' front but I'm not likely to be carrying needle and thread unless I am very remote in which case I'll probably have spares rather than deal with repairs.