This Is Where You Must Store Your Belongings When Wearing a Suit.
When you wear a suit, you don’t want all the trash in your pockets to form ugly bumps. This diagram shows the ideal places to keep things close at hand without ruining the look.
This image from the Art of Manliness tips site showcases the perfect place for all the things you can carry around in a suit. He thinks your phone and slim wallet should be in inner breast pockets, while more awkwardly shaped items such as keys and a large wallet should be in the bottom pockets of your trousers. Whether you want to add a pocket square, pen or handkerchief, there is also a suitable place for everything. Of course, all this assumes that you have these pockets. Not every designer takes pockets into account, but if you have them, make sure you use them.
Where to put things in a suit | The art of masculinity