501 Jeans claim to be the "Original Jeans" and rightly so. 501 jeans were invented in 1873 by Levi Strauss, their namesake, during the San Francisco Gold Rush. Back then, they were called "waist overalls" and were all the rage for minors trying their luck at striking it rich by spotting those elusive chunks of gold. Today, they have an altogether different purpose. They are synonymous with fashion and can be spotted on everyone from the president to teenage celebrities--a far cry from their original use. Now they come in different fits and washes and can be suited to any taste or occasion.
Dress them down. 501 jeans can be worn almost anywhere. However, it is a general rule of thumb that light jeans should be dressed down. Pair the "Original Jeans" in "Snowbird," "Medium Stonewash," "Super Destructed Light," "Deconstructed Light," or "Lightning Blue" with a pair of light sneakers or boots and a t-shirt. This sort of style would be appropriate for day-time wear or out to a casual restaurant. Light jeans also should be worn when performing work around the house, although you may want to get out your ratty light 501s before you start flexing your muscles.
Dress them up. The "Original Jeans" in "Dark Aged," "Rigid Rinse," "Dark Stonewash," "Rigid Green," "Rinsed," "Cracked Dark," or "Perfectly Worn" can be dressed up in certain situations. Although it would not be appropriate to show up at a black-tie event in dark jeans, they can certainly be worn to events labelled "dressy casual" and are a good choice for dates or semi-dressy restaurants. Pair them with a nice button-down shirt or a sweater and wear dress shoes or all-black sneakers to give them a polished appearance.
Fitting the jeans is very important. If you're going for a more polished look, make sure the jeans are not too baggy but not too tight either. They should fit comfortably around and hit a little lower than your natural waist. Baggier jeans can be reserved for casual events, although it is a fashion faux pas to have your boxer shorts showing. See Levi's "Fit Guide" for further information: http://us.levi.com/family/index.jsp?categoryId=3286728.
If you are unsure of the fit you want, it is probably best to go with the "Regular" fit. It is not as tight as the "Original" or "Slim" but does not have a baggy appearance.