They don't actually wear out, they just loose a bit of their pre pumped pressure.
Because ours are so small, & our boot/trunk lid so heavy, ours are pumped up to double the pressure of most used on other vehicles. The bloke who pumps mine up takes them to 3500 PSI, much higher than any others he does.
In the Brisbane area of Oz we have 5 little companies offering a mobile recharging service. It is a very simple process. Mine last about 5 years between recharging efforts, & are still going strong.
I don't know why the Scots, [or the Dutch] ever got the reputation for being mean. [}:)] From what I see here, we Ozzies are more inclined to patch up the old bit, & use it, than any one else.
Hasbeen