For as long as I can remember, I’ve been on a search for the perfect white button down shirt. At first it was a mandatory search, for a white shirt to wear for school performances or to a part-time job in a restaurant. But then, after all of those terrible, ill-fitting shirts purchased from the boys’ department, finding a good white shirt became a sort of obsession, and for good reason: a white shirt is one of the foundations of a classic wardrobe. From that single piece, dozens of outfits for hundreds of occasions can emerge! Okay, so finding my perfect white shirt won’t stop global warming or anything like that, but it can definitely keep you out of those sticky “I have absolutely nothing to wear” situations.

The single most important thing in looking for a white button down shirt is fit. You will want to make sure that the seam for the shoulders sits just above the bone that connects your shoulder and your arm. To find that spot, move your finger down your neck, along your shoulder, until you hit that little bump just before your shoulder rounds out. Also, make sure that you can move your arms comfortably by crossing them in front of your chest and reaching across yourself, as though reaching for the salt shaker at the dinner table. The shirt shouldn’t be too tight across your back or in the shoulders, nor should you feel as though you’re swimming in it. Sleeves should hit your wrists when your arms are bent, as they are when you’re typing. If you cannot find a shirt with sleeves that are short enough, find one with the right shoulder width and take it in to a seamstress to have the sleeves shortened.

For a more feminine fit, look for a shirt with princess seams that should run from just below the breasts to just above the waist. These seams will help to create a contoured look, which keeps the shirt from looking too boxy and masculine. You can also look for a white shirt with details such as a mandarin collar or sweet detailing at the neckline and sleeve hems, such as a subtle tuxedo ruffle, ribbon, or color, which will help to keep the classic white shirt a little less formal and a little more personal.

While there is no shortage of places selling white button down shirts, it’s good to have a solid starting point where you will have a selection of different fits to play with. Banana Republic has a very consistent line of woven shirts, although they are generally very standard with sharp lines. J. Crew also always has collared shirts on hand, but their shirts have more variation from season to season, in the details. Pink, Ralph Lauren, and Brooks Brothers are also excellent places to begin your search. Don’t expect to spend extravagant amounts of money on the shirt, but don’t give into the temptation to buy something cheap that will quickly fall apart; remember, this is an investment into a lasting wardrobe, not a trendy piece that will be out of style next year.

The reason why the white shirt is so important to creating a classic wardrobe is that it can be relied upon in such a vast range of situations. Pair it with a pinstriped pencil skirt and heels for a job interview; with jeans for a picnic; with a circle skirt for brunch with the girls. You can wear it under a blazer or over your bathing suit. There is something about a great fitting white button down shirt that conveys confidence, so that even if you threw it on because you were feeling miserable, you can be comfortable knowing that you look fresh, sharp, and prepared for pretty much any situation you need to wear clothes for.