When you're thinking about investing in timeless pieces, think quality, longevity and inspect details carefully before you buy. We have a quickie 4-step checklist that we run down every time we're making a savvy purchase--it only takes a minute and can help banish regrettable impulse buys.

Quicky Checklist for Identifying Quality Clothes:

• Seams. Pull gently on two sides of a seam and inspect how well it is stitched.  If the fabric spreads easily or if loose threads are visible, put it back on the rack.
• Finishing. Seam edges and hems should be finished, never left raw, which will lead to fabric fraying.  Seams should also allow at least a 1/2" of fabric.
• Details. Buttons and trim should be attached evenly and finished cleanly.  Loose threads and uneven details are usually an indicator of cheap, sloppy work.
• Patterns. Check seams to make sure patterns and stripes line up properly.  A good piece will be well constructed with carefully monitored details.

Savvy Wardrobe Staples That Never Go Out of Style

1. Black straight-legged pants. Look for a good quality fabric like wool and a versatile fit that will go from day to night.
2. Cardigan. Cashmere is by far the best fabric for a timeless cardigan. Look for a colored piece that flatters your skin tone, a hem that hits near your hipbones and a fit that is tight enough to look clean unbuttoned, but loose enough to layer with a tank, tee or button-up shirt.
3. Blazer. We love a good, crisp black blazer with the same fit rules as a cardigan, but unique, colorful pieces along the lines of Suze Orman's savvy jacket trick have totally inspired us to go for more colors.
4. Trench coat. A crisp, belted khaki blazer is a piece you can wear for the rest of your life.  Invest in a quality brand and you might even be able to pass it on to your kids.
5. LBD (Little Black Dress). We've got some great picks and buying tips over here.  Nothing too flashy, nothing too fancy, just a good, classic fit and a fabulous fabric.
6. 24/Savvy Dress (versatile, day/evening). This should be something you could pack in a suitcase for a weekend jaunt to Rome (as if!) and be comfortable wearing while touring the Coliseum during the day and at an alfresco dinner that night.  How about a multi-purpose piece?
7. 24/Savvy Bag (versatile, day/evening). Same idea.  You can never go wrong with a rich brown or caramel leather bag in a classic silhouette.

Photos (L-R) Icon Trench, $298; Eden Cardigan, $89.50; 1035 Jacket, $129; Cashmere Tee Dress, $228 all from jcrew.com