The single-breasted suit jacket, blazer, and sports jackets are the most familiar and staples in every gentleman's wardrobe. Even though most of us would like to buy a single-breasted suit as a first suit because of the versatility of that garment also appropriate for every formal occasion such as job interviews, business meetings and etc
The single-breasted jacket also has various types of waist button stance and it describes the formality of the garment as well.
For instance: single-breasted with two buttons (the most familiar in business suits, blazers, sports jackets), Single breasted with three buttons also called a three roll two (often comes with sports jacket), and then the most formal one is single-breasted with one button (its familiar with tuxedo and dinner jacket).
Predominantly single-breasted jackets and coats are defined by their narrow overlap of fabric with one column of buttons; then most often the single-breasted jacket is familiar with its iconic style which is the lapels and buttons stance of the jackets,
Indeed, if we look at the design of the single-breasted jacket it distinguishes itself with its lapels; the notch lapels are the most familiar, but barely we could see the peak lapels in the dingle-breasted jacket because the peak lapels and show lapels reveal the highest level of formality that's we could see them in black tie and white attires such as tuxedo, dinner jacket, and morning suit as well.
But the notch lapel will always fit in the middle; in terms of formality because it would be easily humanized with both levels.
Whether it would be a business suit, blazer, or perhaps a sports jacket it will maintain the formality of your outfit.
If would choose a single-breasted with notch lapels suit or blazer for your business meeting, everyday office wear and interviews, of course, it is the best choice and it gives a confident and elegant look and my suggestion for you to buy as a first single-breasted suit or blazer the navy blue or charcoal grey colours is always versatile and timeless and it would maintain the formality as well.
Gentleman, one more thing I wish you could find a good tailor to make your first suit for your next business meet or an interview.
Cheers gentleman