You ask what the typical wear cycle is... but that is horribly difficult to answer. I think it needs to be said that EVERY semi-auto pistol extractor, no matter the design, is going to last FAR longer if the pistol is ALWAYS allowed to strip a round from a magazine and NEVER permitted to slam over a chambered round. Or an empty piece of brass for that matter.

You can see how a minimal extractor issue can quickly snowball in to a bigger extractor problem?

A new coil spring under the extractor is perhaps the quickest fix for many (not all) FTExtract problems.