1. Do you bother, or just replace with new inner
Bother
2. Does the glue have a shelf life?
yes it seems to dry out but this is measured in years
3. How long do you leave the glue before applying the patch – leaflets say 4-5 mins but seems like a long time
as long as it says i figure they know how to use their stuff
4. How long do you leave the patch on before removing the plastic backing
Usually peel it off first tbh had a few issues getting it off in the past
5. Do you trust repaired inners completely?
As much as any other innertube but i would not tell it my pin number 😉
More prone to slows tbh so I tend to have them as my spares in the camelbak and new ones on the bike.
I dont change them after I have done a trail side repair though