Demi Lovato is only 20, but she's already developed a signature style -- and it's both rocker chic and rocker chick. While the singer changes her hair cut, color and length on the regular, she is incredibly consistent with her attire, and her closet is loaded with tons of black leggings, black leather, studs, glossy patent leather stilettos and minis that show off her shapely legs.

This is Lovato at her very best during her first season as an 'X Factor' judge. She was leggy and cloaked in all black, tough and girly, and those moves have become her signatures.

She sometimes adds twists in the form of pops of color via accessories, but for the most part, this is her template and it works for her.

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Lately, Lovato has been sporting a buttery blonde shag with loads of layers. It's a bit of a frumpy look for her, especially when we're used to her going so utterly glam. Here, she has the same cut, except in a brown hue, and while she may have been doing a promo tour at radio stations when this photo was taken, she looks like a cadet trying to be glam with the embellished leggings and studded combat boots.

It's definitely not her most successful or enviable ensemble. Something is off about this attempt at casual.

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This hair is decidedly more glam and, well, better. Her jacket could double as a weapon that puts someone's eye out, which means it's uber fashionable and functional.

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What's Right:

All black and layers -- that is what we've come to expect from Lovato. This look was youthful and universal and is very easy for her dedicated legion of Lovatics, most of whom are in their teens, to copy.

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Even when she was walking wounded with a broken ankle in early 2013, Lovato was adorned in studded black leather and took care to wear a fashionable cast. This is another signature look for her.

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She broke with her beloved basic black in favor of a blush mini paired with sky high heels, a topknot and sunkissed skin. This was easily her sexiest and most femme look ever and proved she can pull off something other than black.

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Lovato really showed her deft management and mastery of the color black by pairing a cropped leather jacket and opaque tights and lacquered heels with a loud blue and pink floral print. This was a young, modern and hip look that teen fans could copy (without using all of their allowances or minimum wage job salaries).

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What's Wrong:

When hosting an awards show, Lovato overdid it with a super short Falguni peacock dress and 'I Dream of Jeannie' hair. It was almost a caricature.

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The chunky heels, paired with a babydoll hem mini, were way too '90s -- the decade in which the lovely Lovato was born. This look, complete with the messy, big hair, was incredibly dated.

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How to Fix It:

Demi is clearly in a zone -- and in her comfort zone -- when dressed in black, but she can achieve a similar result when she goes with color, like she did with this splash of scarlet. She topped it with her security blanket, aka a black leather jacket, and paired it with heels that were utterly maj.

Frederick M. Brown, Getty Images

Her Saint Laurent mini was uber sexy, but we just don't love the shaggy, soccer mom hair. For someone who has been so experimental with her locks, she has been playing it way too safe as of late. She would have elevated her overall style here with a long or a dark coif.

Perhaps, though, she damaged her hair from all the follicular tricks she pulled over the past year. It's a distinct possibility.

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Her love affair with Topshop frocks has helped bring the brand into focus. It's also why she outshone her fellow judge Britney Spears every night on 'X Factor.'

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Again, we love that she knows how to approach black and leather --we just think the hair needs to be re-modernized.

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