Stripes on suits are always vertical but come in a number of different styles. The first, foremost, and most classic is the pinstripe.
A pinstriped suit, particularly a navy pinstriped suit, is an extremely traditional look, almost a uniform of sorts for the businessman.
Pinstripes, as the name suggests, are very narrow though generally prominent stripes, most often in white, although grey is a not-uncommon choice, especially on dark grey or black suits.
Occasionally one will find stripes in other colours – pastels were in vogue for a time – though these suits will quickly become dated once the fad has passed.
Additionally, they limit the opportunities for wear, being both informal and somewhat more difficult to match with shirt and tie. A classic, white pinstripe never goes out of style.
These, and all stripes, help to make the wearer appear taller, as they draw the face upwards, and can make a heavyset man appear thinner, by breaking up and drawing attention away from the solid midsection. This is particularly true for thin, close-set stripes like the pinstripe.
There are also other stripes, including the thicker chalk stripe as an option for the gentleman’s wardrobe.
These stripes, which are generally set farther apart due to their greater width, are significantly less formal than the pinstripe, and while continuing to provide the appearance of increased height, are less appropriate for large men, as they can draw attention to one's girth.