I never expect random chips bought off AliExpress/eBay/Amazon/etc to work, much less be genuine. I do expect breakout modules and the like to work, though I don't expect them to contain genuine parts. (That implies I'd never source from these places when it's a critical function.)
I'm always surprised when people expect grey-market crud to perform just as well as top-dollar stuff....
So far I've seen a ton of fake audio op-amps.
For discrete parts like transistors things are much simpler. Just build a simple test rig and test a few parameters. If they fall within the specs they're probably good enough. Of course it's not worth it to do this for jellybeans like 2N3904, but when some parts get obsoleted without a replacement (or they're too pricey) there isn't much else a lone hobbyist can do.
Links? That sounds fun...
I'm Canadian, and last I checked, the shipping costs to get parts from places like digikey was just ridiculous.
In professional engineering, where time is money, Digi-Key or Mouser is always more efficient, if they've got what you need. For personal stuff, where the value of your time is ~zero, the opposite can be true.
If I were working on something more important that dinking around for fun, sure, I might care a bit more about what's actually on the board. But as it is, the clones are more than adequate for my needs, particularly at their price point.