The early bird catches the worm - or could they be fake?

Now I get why people buy expensive sunglasses: they just look so much better than the cheapie ones. Like these purple Coach shades I recently thrifted at my fave new thrift shop, Canadian Thrift. They're just so substantial - and they're purple to boot!

Actually, I left them there for a day to think about it before going back and scooping them up. The owner told me today numerous folk have come in asking about them. Ahem.

Now I'm not an expert in detecting designer knock-offs - though I have rather quickly passed over what must be the poorest imitations of Prada and Burberry handbags in some thrift stores - but these glasses just felt right; they had wonderful detailing and a certain weight to them that just made me want to be all movie-star poseur. The lesson I'm choosing to extract from this latest thrift venture? Don't underestimate your gut when thrifting!

Do you have any tried and true tactics for detecting fakes when thrifting? Is it a gut feeling for you, or do you have extensive knock-off knowledge? Please share!