The right sunglasses never go out of style. But who hasn't been swayed by designer frames, or a duty free bargain, and ended up with shades that don't suit? The key to successful sunglasses shopping is to allow ample time, and to get a second opinion - it's hard to judge your reflection with shades on. Better still, get your shopping partner to take photos of you.
The right style for you will depend on your face shape, but think about frame colour, too. Black can be harsh against some skintones, so if you're prone to looking washed out try tortoiseshell instead.
Finally, it's worth investing in your sunglasses, so skip the cheap and cheerful pairs in high street shops. At best, these will give you 'nose dents', at worst they won't offer adequate UV protection. Here's how to pick the right pair for you.
If you have a baby face, with full cheeks and rounded chin, you're aiming to add definition and make your face look longer, rather than softer, or wider. Go for angular frames, and avoid deep, oversize lenses which will hide more of your face and make it look shorter. Petite sunglasses are a big trend for 2012 (in response to the ubiquitous oversize styles of recent years), so you're in luck.
Celebrities with round faces: Renee Zellweger, Drew Barrymore, Charlotte Church
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You have a wide forehead and cheekbones, tapering to a proportionally smaller chin. To balance your face and stop it looking top heavy, go for small square or rounded frames (try Ray-Ban Wayfarers) , and avoid frames that are much wider at the top than the bottom.
Celebrities with heart shaped faces: Rihanna, Kate Moss, Christina Ricci
A square shaped face has a strong jaw and broad forehead. You're looking to add length to your face, and soften the angles of your chin. Oval and round frames will flatter your features, so avoid angular styles with sharp corners. Small, narrow frames are a safer bet than big lenses, as they will make a short face look longer.
Celebrities with square faces: Cameron Diaz, Minnie Driver, Sandra Bullock
If you have a long, slim face, opt for wide frames and big lenses to make it look shorter. A low bridge is more flattering on a long nose than a high bride, too. 70s cat eye shapes are a big trend this year that'll work for you.
Celebrities with oval faces: Liv Tyler, Gisele Bundchen, Sarah Jessica Parker
As with haircuts, most styles will suit an oval face (longer than it is wide, with a slightly wider forehead than jaw). Show off your natural symmetry with frames that are the same width as the broadest part of your face.
Celebrities with oval faces: Jessica Alba, Sienna Miller, Alexa Chung
Find the right sunglasses for your face shape below: