What do you mean by "tyre wall"? You mean sidewall? --> patching sidewall is super no no as stresses is the highest on the sidewall. Chances of failure is relatively high.

If its on the tread & done properly & properly inflated , tire should be able to withstand till its end of life.

Sorry, I do not really understand what is the "wall behind the tread"

But anyhow usually glue should last at least 3-5 years. Hence you should always make sure you check and maintain proper tire pressure.