A blazer sits in the gap nothing else fills. Easier than a suit jacket, smarter than a sports coat, and exactly right in all those situations where a full suit is too much and an open-necked shirt is not enough. A navy blazer over grey flannels or a good pair of chinos is one of the few outfits that has never once been wrong, anywhere, in anyone's lifetime. Made to your measurements it fits in a way no rail version manages, it outlives three or four cheaper jackets, and people will ask you where you had it made.
Why the navy blazer never goes away
If you can only have one jacket, make it a navy blazer. Grey trousers and it is office-appropriate. Khaki or cream chinos and it is a Sunday lunch. Dark jeans and it is a dressed-up evening. It takes any shirt you put under it, white, blue, striped, and it works with a tie or without one. It is right in a relaxed office, at a business dinner where a suit would be heavy-handed, at a wedding where nobody has specified black tie, and across a very wide range of evenings out.
The classic is navy, and we mean a proper deep navy rather than something washed out. Fine worsted or a soft barathea. Buttons in brass, horn or a dark shell, never the shiny gold-plated things that look tired within a year. Two or three buttons at the front, working cuffs, two or three flap pockets and a breast pocket for a square. Kept plain it is quietly perfect. In the right cloth it becomes something more personal.
If you already own the navy one
Navy is the standard, but a charcoal or dark grey blazer does almost the same job. A dark green one is unusual and far more wearable than people expect. Burgundy or oxblood has a period feel that lands well socially and in creative rooms. Whatever the colour, the cloth is what decides it. A blazer earns its place by draping well, holding a press and ageing with some dignity instead of fading and pilling into retirement.
For Chennai, a linen blazer in natural, stone or pale grey is hard to beat, both for the weather and for the kind of daytime function we all get invited to. Yes, linen creases. That is what it does and it is part of why it looks good, so do not fight it. It also breathes in a way wool simply cannot. A linen blazer in a good European cloth is one of the most enjoyable things we get asked to make.