The fashion industry is a very rapid industry you have to stay ahead of the game at all times and can not afford to fall behind. In the world of fashion, the four seasons are combined into two seasons while the average person has Spring, Summer, Fall, and winter. In the fashion industry spring/summer start from January - June, and fall/winter start from July - December.
As we all know in any job or business being early is being on time and being on time is being late, this rule plays a big factor in the fashion industry. A designer must have a collection ready ahead of the season to come. Also in most cases have previews available or release ahead of time for their clients to purchase and as well see what they will be releasing for the upcoming season.
Furthermore, some clients likes the VIP treatment because the fashion seasons do not exactly fall in the calendar seasons, it makes it more important for designers to be early for their clients but on time in the fashion world, allowing clients enough time to see what they want to purchase and make their purchase for those season, holiday, and event. In most cases designer starts to design a collection a year ahead of time to ensure time to fix the collection is perfect in time for release if needs to be adjusted, but also giving them plenty of time for production, promotion, and ads.
Staying on top of trends, and style, and being creative in delivering current and new designs to your clients is one of the most if not the most important parts of the fashion industry. Clients like to have fresh designs or new designs that will have them look good, feel good, and most definitely look good in their pictures, post, or videos. If they are an influencer they want to look fashionable when going viral.