Everyone has their favourite item. A go to piece, that if they didn't give any thought to, they'd probably find themselves wearing each and every day.
Mine is a Sunspel loopback sweater.
It has to be, I have two of them.
The reason anyone gravitates towards a particular item will usually be three-fold: fit, quality, and versatility.
The loopbacks have quality in spades. They're outwear pieces that don't require dainty handling or concern about wear and tear. Both of mine are over a year old and both look as good as new. I know, as I've compared them to ones in-store - sad, I know.
As for fit, someone called me trim the other day (thanks!), but while these jumpers are fitted they also provide a bit of cushioning, so you look less rake-like and more like you're carrying some muscle. No bad thing.
Finally, there's versatility. Round necks work with both shirts and t-shirts. The colour of the jumpers helps too. Plain in tone, they settle in nicely with jeans, chinos, trainers, shoes, and shirts of every colour.
Owning two - and attempting (yet failing) to buy a third in the sales - makes me a fair fanatic of the Sunspel loopback, but when you find something of such quality that fits so well, it's hard not to stock up and make it a key component in your wardrobe.
You can find out more about the design of the loopback range on the Sunspel blog.