Moving on from the jacket sleeves, we have the pockets, which present a variety of options, all at differing levels of formality. The most formal are jetted pockets, where the pocket is sewn into the lining of the jacket and only a narrow horizontal opening appears on the side of the suit jacket. These pockets, being nearly invisible, contribute to a very sleek, polished appearance, and are most frequently found on formal-wear. The next style, the flap pocket, is slightly less formal, though it is perfectly acceptable in all the circumstances where a gentleman is likely to be found in a men's suit. Flap pockets are made identically to jetted pockets, but include a flap sewn into the top of the pocket, which covers the pocket's opening. These are the most common pockets on men's suit jackets, and in the very best, are fabricated so that the wearer may tuck the flaps inside, mimicking the jetted pocket. There are also diagonally-cut flap pockets known as hacking pockets, though they are somewhat less common; the hacking pocket is derived from English riding gear, and is most prominent on bespoke suits from English tailors, particularly those traditionally associated with riding clothes. The least formal are patch pockets, which are exactly what the name implies: pockets created by applying a patch to the outside of the jacket. Patch pockets are the most casual option; they are frequently found on summer suits that would otherwise appear overly formal, as well as on sports jackets.
On the subject of pockets and things the conscientious wearer avoids, there are a few guidelines for utilizing the pockets on suit jackets. While the outside pockets on most jackets are functional, placing large bulky items – including the hands – in these pockets will distort the silhouette of the jacket. Keys and other sharp objects should be kept away from the jacket pockets, as they can damage the lining, leaving holes into which small objects are invariably drawn. Many jackets come with the pockets sewn shut, and while it is generally better to open them, those who have difficulty remembering what to avoid may find it beneficial to leave them unopened.
The side pockets are not the only pockets on the jacket, however. Some men's suit jackets, particularly bespoke and finer made-to-measure offerings, include a small ticket pocket above one of the side pockets, generally on the same side as the wearer's dominant hand. This pocket is rarely used in modern times, and serves more as an indication of the suit's quality. Moving up the jacket is the breast pocket, which is always open, and into which only one item is ever placed: the handkerchief or pocket square. The reason for this is twofold: First, like the side pockets, any items placed in the breast pocket create lumpy projections which distort the sleek appearance of the suit, and second, the breast pocket and the inside left pocket share the same space in the jacket's lining, meaning that objects in the breast pocket tend to force items in the inside pocket into the wearer's ribs, which is quite uncomfortable.
Inside pockets vary greatly, with some jackets having only one, usually on the left, though it is more common to have pockets on both sides. These pockets are generally large enough to carry a checkbook-sized wallet or card case, as well as a pen and perhaps tickets or other similar papers, though one should be careful, as bulky items, even in the inside pockets, can distort the jacket's appearance. On bespoke suits, the options for pockets are only limited by the wearer's imagination, as a good tailor can create specialty pockets sized to hold a variety of useful items. In today's world of technology, such pockets provide the perfect place to store items like cell phones and iPods.