i've been pondering this question the last few days, do not know why - how something can be 'passe' or 'over' in terms of overall trendiness but for the right person they can wear that element for decades and always look fantastic.
I think it comes down to your own personal style aesthetic. In that gorgeous pic rae posted (ty rae!) my eye went to the gorgeous oatmeal tank dress with the lace stencils - to die for!!! i have a very strong edwardian femme element to my style, and i'm always incorporating lace in various ways. So while that type of dress will be trendy now, and other people may wear it as a 'trendy' piece, for me it would be closer to a signature part of my look and i could wear it for years (if a think knit like that would last for years, which it won't).
So for a classic/elegant type person who wears a lot of black, they could get those (truly droolworthy) spiked loafers and 'get away' with it while studs are on trend, but feel awkward wearing them in a year or two.
But a rocker/edgy/apocalyptic warrior princess could wear them for decades, as leopardluxe says, as they are an expression of her true style center.
Which is why Angie says, "if X is your thing, when X is in style BBQ!" FWIW, i think studs as a trend are going to flame out in the next 6-9 months. Happy Day all! steph