When you're on a strict budget, the very idea of buying several versions of a single item seems laughable. You may imagine Kim Kardashian fondling her collection of Birkin bags and think that multiples are a luxury. And they absolutely are. You need more than one pair of panties and more than one pair of socks, but you needn't purchase multiple identical pairs and you needn't purchase them all at once, should finances prohibit.

However, some items can be so difficult to track down that buying them in multiples really does make sense. And might be worth fudging the budget for a month. In my opinion, the short list includes:

Bras

I'm relatively sure that few women can saunter into a lingerie department, pick up any old 34B, and walk out with a perfectly fitting bra. When you find that ideal brassiere - the one that fits, feels amazing, works under your clothes, and makes you feel sassy - it's probably wise to nab more than one in a single shopping trip. Of course, if you're a lingerie connoisseur, this may not appeal. But if you shed bitter tears every time you go in for a fitting, consider buying multiples when you DO stumble across a fabulous bra.

Tights

If you're anything like me, you snag a pair of tights every time you THINK about nails or barbed wire or sandpaper. Especially patterned or sheer tights. If you splash out on a pair of neon green tights that have extremely limited use within your wardrobe, buying one is fine. But if you happen upon a fabulous-fitting but slightly delicate black patterned pair that will work with half your closet, or suddenly find that your burgundy pair is getting weekly wear, pony up for multiples. And stop thinking about barbed wire.

Layering tops

Depending on your climate, your layers may be long-sleeved, short-sleeved, sleeveless, or all of the above. But regardless, if you unearth a 3/4 tee that fits perfectly to your torso and plays well with your unique proportions, it might be worth your while to buy it in multiple colors. You could also consider purchasing and stashing extras in black, white, or your preferred neutrals ... but only if your budget allows and only if you wear out your duds fairly quickly. Backup clothing in storage is great in theory, but often gets forgotten or supplanted by newer, better versions.

Perfect jeans

Another Holy Grail item, am I right? Fantastically flattering jeans get frequent, hard wear and can be extremely difficult to find. That combination of factors makes them ideal candidates for multiple purchasing. I prefer to do two pairs in the same size/fit but different washes, when possible.

Again, multiples aren't for everyone. They take up space, create redundancy within closets, and require some budgetary leeway. But, in my experience, certain high-use, difficult to locate pieces may be worth the risk.

Do you buy multiples of any items? How do you determine which ones should be bought in bulk? Frequency of use? Fit frustrations? Or do you avoid buying multiples altogether?

Sally McGraw is the author of Already Pretty, a daily blog about the intersection of style and body image.