I assume all gun springs wear out in time. I've read that the recoil spring is the first to go, and that SIG Sauer recommends replacing recoil springs after 5,000 rounds. As I understand it, this is a generi recommendation -- it is not specific to the P238.
I found the article: http://throwinglead.com/index.php?pa...ning_guide_SIG. A maintenance schedule is toward the end.