Breast handkerchief is something we hope never goes out of fashion. It is an easy way to make an outfit so much more thoughtful and interesting. Whether you are dressed or casual, you can almost always add a handkerchief to make it all a little better.
Jeans, a plain T-shirt, a blazer and a handkerchief in a beautiful pattern or a bright color is a spot right outfit for casual situations, eg After work or a beer with his friends.
A full suit with matching handkerchief and shirt is incredibly neat. Many people make the mistake of matching handkerchief to tie, which makes it easy to look like that one has a work wearing a uniform. Navy blue suit, white shirt and white handkerchief with a low-key pattern is a perfectly dressed look neat celebrations, festivals and the like.