Denim never goes out of style, but there are seasons when your old, reliable five-pocket jeans simply aren't enough. This is one of those seasons.

The jeans legging - aka jegging - is still going strong, and denim designers are also talking up the chambray shirt, asymmetrical motocross jackets, cutoff shorts and, still, the boyfriend pant. There are trouser styles and waistcoats for work, and, "rip-and-repair" jeans are a must for weekends.

Ralph Lauren had overalls on the runway and showed jeans under an evening gown. Even babies are getting premium denim.

And a denim-on-denim outfit, sometimes considered a fashion faux-pas in the past, is a bona fide trend.

"The American denim look is everywhere - it's in the air, it's all over the world," says Patrick Robinson, creative director at Gap. "The workwear feel is hot, especially for guys, and there's a sexy look for women. ... It's about cool Americans and how they live and we're trying to export that around the world."

Denim is proving a strong springtime seller in stores, says Stephanie Solomon, vice president of fashion direction at Bloomingdale's. She is particularly fond of the shorts and leggings paired with striped T-shirts.

"It probably has never had a larger impact on what we wear every day," agrees Durand Guion, men's fashion director for Macy's. "We had gotten just about as casual as we can get without getting in our pajamas, so we're looking to incorporate denim into our lives at least five days a week, but not just Saturdays. We're looking to step it up. You can wear a button-down denim shirt with a tie."

Helmut Lang co-creative director Nicole Colovos thinks people like that they can put their own spin on denim. And no pair of jeans looks the same on two different people.

"It's so individual, from how you wear it in, how you style it. The fit is molded to your shape," Colovos says. "You don't want someone else wearing your jeans."

Finding the best fit is trial and error, she adds, but once consumers find a denim label they like, they tend to be loyal.

Denim leggings aren't saggy and baggy, and that flattering, lasting shape is part of their appeal, says You Nguyen, Levi's senior vice president of women's merchandising and design.

He says he can't overemphasize the importance of the legging right now. It further evolves the skinny jean, which has moved from trendy to staple status, and it complements the tunic top and the slouchy blazer that are being touted for spring.

"Our leggings business is on fire, at all price points and at all retailers," Nguyen says.

On the flip side, the boyfriend skinny jean - with a looser waist and hip but a narrower leg - remains popular.

"I don't believe that denim has ever really left the fashion "trend,' but what we're seeing now is that for a few seasons, denim was influencing sportswear, making sportswear more casual. Now sportswear is influencing denim," Nguyen says.

Look for lighter shades of denim as the weather warms, and a lot of distressed finishes, too, sometimes with purposeful patches.

G-Star collection stylist Remco De Nijs' favorite denim fabric right now is the traditional Japanese selvage out of the brand's new Raw Essentials collection. He says the fabric has a very authentic denim hand, which juxtaposes nicely with modern silhouettes, such as the company's signature Arc Pant, which has a low-slung top and exaggerated tapered leg.

(Selvage denim, De Nijs explains, stands for the tape on the edges of the denim looms. Traditionally every brand had its own edge. That is how the manufacturer recognized the brand.)

G-Star also has broadened its denim color palette from a dark raw denim to even some fabrics that forgo any indigo coloring at all.

Helmut Lang offers some denim items that have had the color stripped away and then added back for an irregular, imperfect look.

"Three seasons ago, we were in the cycle of very dark denim," observes Nguyen. "Now we're going back to true nature of denim, which is denim aging down. You love a pair of jeans so much that you refuse to let it be worn out."

Going forward into fall, though, trend analyst Tom Julian expects to see colored denim as well as patchwork. There will also be more players in denim next season: Proenza Schouler is collaborating with J Brand. One style will be made of Japanese stretch denim hand-painted all over to create texture and dimension.

"For fall 2010 we are exploring ideas closer to home," say Proenza designers Lazaro Hernandez and Jack McCollough in a statement. "Urban elements are important as is the idea of uniforms. Denim fits the bill as the most ubiquitous item in most people's wardrobe."

If you go for the all-over denim look, you'll need to wear a variety of weights and washes, and try a polished bottom with a relaxed top or vice versa, advises Gap's Robinson. It could be different shades of blue, blue with black - or white.

For those reluctant to go head-to-toe, accents on bags, hats and sneakers allows for a more subtle secondary denim piece.

Personally, Robinson says, he's really into the look of a chambray Western shirt with slim-leg jeans. "The attitude is happy and cool. I also love this time of year when you wear the denim jacket."

And it is about "the" denim jacket, not one of many. Denim, by its very nature as a rugged cotton twill, is strong, building for many years as it becomes weathered - sometimes even a little tattered - but very rarely truly worn out.

"Denim tells a story," says Colovos. "You know where you got that rip or grass stain. Denim lasts for a long time and sometimes it's better with age."