For as long as anyone can remember you could have bought a fake Rolex for very little money. And this is fine.
But of course if it falls part in few months don't complain. At least you didn't paid much for it (hopefully).
Sometimes you do notice a pair of shoes or pants last longer than usual. I had a pair of pants branded Lee Dungarees "Can't bust 'em".
We all encountered these things. Sometimes it's worthy to spend a little more and get something which would last longer.
This of course doesn't apply to everything but we try to get 80% of the item with 20% of the cost. This can only happen when buying a quality item used.
Example: A 2005-ish Mercedes CDI. You can get a nice one for 20% of what it cost when new. And if it was nicely maintained then for sure you have 80% of it.
Don't pay 80% for it new just because it has similar features to a proven, quality item from another manufacturer (say Hyundai Genesis vs Lexus LS).
Let depreciation work in your advantage.
In very fast moving industries (cell phones etc) I am not sure if this holds true. You may need to pay substantially more than 20% for a very mildly used flagship phone few months after its replacement is introduced. I think that it will still outperform a comparatively priced budget phone and it may last longer too (f anything it may still offer decent performance).
Bottom line is: You want it now, if you care about fashion, be prepared to pay dearly for it. But remember: What you overpay now because you are a fashion slave, you don't pay on other crap which needs attention ($$$).
Happy saving and intelligent spending everyone;D