I put this tee in my cart to round out a discount. It is all I have worn since.

I am 60 years old, and the best thing in my wardrobe this year is the one I never meant to buy.

Let me explain, because I suspect a good many of you will recognise yourselves in this.

I have ordered from Sofia Wellington a few times now, ever since a friend of mine turned up to bowls in a linen top she would not stop talking about. They run a standing offer where a second piece takes ten percent off the whole order, and I have never once in my life been able to leave a discount like that sitting there. My husband Graham says it is my one vice. He is wrong, I have several, but this is the cheapest of them.

So a few weeks ago, with something else already in my cart, I went looking for a second piece to make the numbers work. I picked a plain tee called the Thea, in rose, mostly because it was the least expensive thing I liked the look of. I did not read the reviews. I did not study the photographs closely. I clicked it into the cart the way you drop a magazine onto the belt at the checkout.

Three weeks later I own it in three colours, and the top I actually meant to buy is still hanging where I left it.

Here is the thing I did not notice when I ordered it, and the thing everybody else notices immediately. The Thea is not a plain tee. Running down the front is a neat row of small buttons. They do not open anything. They do not do anything, really. But they turn a basic top into something that looks chosen, if that makes sense — the way a plain dress with one good detail suddenly looks like an outfit.

My neighbour spotted them from over the fence. My sister, who is 63 and does not hand out compliments easily, looked at it and said that is smarter than what you usually wear. From her, that is practically a standing ovation.

The second thing is the hem. It is cut a little longer at the back than the front, so it drapes down over the part of you where trousers do their least flattering work. I did not know how much I wanted that until I had it. You can wear this tee with white trousers, which I normally avoid the way I avoid the scales in January, and everything is quietly covered without the top looking like a tent.

And the fabric is properly breathable — it does not cling, it does not stick to the small of my back in the car, and the rolled-up sleeves land at exactly the spot on the arm where sleeves should land and almost never do.

I started keeping count. There is a notepad in my kitchen where I write the shopping list, and one morning, a little embarrassed at myself, I started a tally of how many times I had worn the rose one since it arrived. When the count hit double figures inside three weeks, I went back to the website and ordered the white and the blue.

It is early spring, and I have been wearing this tee for three weeks straight, which tells you something either about this top or about Tauranga. A cardigan over it on the cooler mornings, on its own by lunchtime.

My daughter Claire saw the rose one on our Sunday video call and made me hold the laptop closer so she could see the buttons. She has now asked for one in white, which is the first time she has asked me for clothing advice since she left home.

They come out of the wash soft, they hang dry overnight, and they do not need ironing unless you are fussier than I am. It is, and I know how this sounds, the closest thing to a uniform I have had in years. It has taken the guesswork out of getting dressed, in the best possible way.

The Thea is $79.95 at the moment, down from $159, because Sofia has brought the summer pieces in for a first run and demand has already moved quickly. I want to be honest with you the way I always try to be. At the full price I do not know that I would have gambled on it, because I did not know then what I know now. At $79.95, the only mistake I made was ordering one colour the first time instead of two.

Because here is the arithmetic that matters. The offer that got me into this in the first place works on the tees as well. Two pieces take ten percent off the whole order, three take fifteen, four take twenty. Two Theas in different colours still comes to less than one forgettable top from a shopping centre, and I can promise you the Thea is not the forgettable one in this story.

I also finally read the reviews I skipped the first time round. 4.8 stars across more than nine hundred women, and over and over the same story as mine — that it quietly became the top they reach for most.

If you and I were sitting on my back deck right now with a cup of tea, this is what I would say.

I would say that the tops made for women our age are usually punished for being comfortable. They get made plain, boxy and apologetic, as though comfort were something to be embarrassed about. The Thea is the first tee I have owned in years that feels like a soft old favourite and looks like something I picked out on purpose.

I would tell you the rose is the one I reach for most, that the white goes with absolutely everything you already own, and that the blue is the one people comment on. There is a green for the bold among you, and an orange I am still thinking about.

I would tell you that the popular colours thin out quickly at this price, because that is exactly what happened last time I wrote about a piece like this. And I would tell you to order two colours, not one — partly for the discount, and mostly because you will be back for the second one anyway.

This is a single pre-season run. Spring has only just begun, it will be full summer before you know it, and by December you will want something exactly like this already hanging up.

While the colours are still there.