>>1344
I don't live in the US either, so I know how it is, it took me a while to build up the collection I have. Those who search long and hard enough are rewarded...
No, buckling springs don't go bad on their own as long as you don't mess with them, and Yes, there is a way to replace them using a toothpick or something I believe, you don't need to if they all work fine though so don't worry about it.
What you *might* have to worry about is that the Model M keyboard assembly is held together using melted plastic rivets that eventually break off over time and cause the keyboard to not feel/sound good anymore or even not function properly. This can be remedied by replacing the rivets that break off with screws and washers as illustrated in pic related. Your Model M might be in good enough condition that it doesn't need it, though. Give it a gentle shake to hear if there are any small plastic parts rattling around inside, that would likely be broken-off rivets.