In scrutinizing fashion, we must understand that this is a practice with temporal and spatial variations. Men's fashion, in particular, differs so much in every temporal period and in every region. Fashion may also represent a period's preferences and logic, and a people's culture or their drifting away from it.
Therefore, we cannot say which fashion is actually "in" and which is "out" considering the subjectivity of the topic. Various fashion genres have also emerged that it is difficult to simply categorize fashion according to sexes.
It is a common notion that men's fashion can be less complex than women's. In my point of view, men's fashion sense also requires an intricate amount of effort, although their key considerations could be different from that of the other sex. While women commonly search for fashion ventures which will suit their aesthetic needs, some men prefer to look at fashion in a practical manner.
One aspect that most men consider is the material and the quality of the clothing or accessory that they are using. Men prefer things that do not degrade instantly or only after a few uses, which is why they would favor stores or boutiques that sport good quality and durable materials of which the products are made.
Durability is not the only concern in this aspect but, consequently, the aesthetic quality of the material. Good quality materials do not fade or stretch out easily and can therefore look good even after many uses and washes.
Men would also become conscious about the actual purpose of a particular detail or accessory before deciding to use it. This is probably why a man wearing polo with exaggerated ruffles on it is not a common site.
Wrist watches are among the most favored accessories basically because of their ability to tell time. From the classic leather or gold band, many other novelty designs have developed and have caught the attention of "fashionable" men.
Sunglasses are also accessories that actually serve a purpose while making one look trendy. When men are going for a formal look, the traditional tux, and bows / ties are always welcome.
Some men also take time to coordinate their fashion choices with their physical appearance and other pieces of clothing or accessories. There are standard rules in the concept of coordination which are quite easy to follow once you get started, like which colors, size, or shape can effectively emphasize the body part or facial feature that you want to show off; or which clothing type can make your built seem lean. Knowing this also helps men to decide which clothing / accessories they should add in to their wardrobes.