I'm not sure why it's considered a "must-have" for fall this year, since I've always associated plaid with fall every year, but this year, it's especially hot in everything from shorts and pants to full plaid-print dresses to accessories. If you haven't worn plaid since wearing your boyfriend's over-sized Abercrombie & Fitch flannel shirt 10 years ago, take a hint from Mrs. Beckham and add a little bit of plaid to your wardrobe.

Sunday - Just because it's autumn doesn't mean you can't keep wearing shorts, as long as they are made of cool-weather appropriate fabrics like wool. If you go with a truly short pair of shorts, like these Sophomore Shorts by LaRok in chamois plaid, stay warm with tights underneath (whether they are footless tights is up to you). If that's too short, wear knee-high boots with these longer tab-waisted shorts that hit just below the knee by Billy Blues.

Monday, back to work - Did someone say skinny pants? Yeah, I didn't hear that either. Thankfully, Fall 2006 also looks to the other end of the spectrum with wide-leg trousers. Alice+Olivia makes a pair of tweed trousers with an extra-wide waistband in chocolate plaid. For something more subtle, try the glen-plaid by Diane von Furstenberg. Of course, if you don't have $400, Target has a pair of blue/gray plaid pants by Mossimo Black for $23. A crisp white shirt is perfect for all of these trousers.

Tuesday - Short and pants are fine, but when I think of plaid, the first thing I think of are skirts. I think it's the result of years in private school, and a pleated blackwatch plaid skirt by Isaac Mizrahi for Target takes me back. For a naughty schoolgirl, Dorothy Perkins has a red plaid mini with a tiny bit of black lace peeping out from underneath. If you have $2,000 to spare, you can go with Alexander McQueen's short plaid kilt. If you're not quite a schoolgirl, you can be the Head Mistress in Nanette Lepoore's plaid skirt in chocolate.

Wednesday - A crisp white shirt is a natural with plaid on the bottom, but if you're a jeans-wearing gal, you can put plaid on top with any number of plaid flannel button down shirts. If that's a little too Paul Bunyan for you, Ivy adds a ruffle to the front, making you the most feminine lumberjackette to ever swing an axe. Even more feminine is a sheer blouse by Cynthia Steffe with velvet details, or a sateen-finish blouse by Burberry in gray (my favorite!).

Thursday - If you can't get enough plaid, wear it all over in a dress. Alexander McQueen's casual line McQ has a 100% cotton flannel plaid dress for $485. The plaid print is classy, but the zipper all the way down the front makes it sassy. Try Marc Jacobs brushed plaid dress in petroleum black-blue, or a jumper-style in blue plaid over a body-conscious turtleneck or a fitted white button-down shirt from What Goes Around Comes Around for daytime. Bebe's red plaid bustier dress with black lace trim is perfect for a night out.

Friday - Plaid is showing up in accessories from head to toe. Urban Outfitters has a headband in different types of plaid that'll go great with a complete school-girl look. These flats by Delman with a safety pin that echoes plaid kilts are cute in both brown and red. Charles David has a pair of rounded toe glen-plaid pumps that are a feminine take on men's wingtips. Bettye Mueller's pump has brown plaid in the front alternating with a different print. Of course, you can always go with Burberry's rain boots, which I tried on, but felt too silly wearing in the eternal sunshine of LA, or Target's olive plaid take on the same galoshes.

Saturday - Maybe you're not ready to add plaid to your wardrobe of wearables. Stick to plaid in bags. Paul & Joe has a totally adorable change purse at Target. Juicy Couture has plaid in everything from a little bowler handbag to a large tote for a weekend getaway. The Burberry plaid is a classic print that will never go out of style, and in updated shapes and adorned with gold chains, the Margaret Drawstring is perfect.