I wear both 5″ and 7″ cycling socks but prefer the 7″. I’m not sure why. My calves are skinny I’m told, so they stay up easily. I prefer to think of my calves as lean and strong, like those that only long miles in the saddle produce.
And, I prefer wool, even in the summer. They are never too hot. And, they keep the feet warm even when wet. They also seem to provide more cushioning for the balls of my feet on long rides.
I wear 7″ wool socks all year.
PedalWORKS 
The only thing worse than 7” or higher socks is no socks… 😜 I just don’t get the appeal and “sock game” is not my thing. I prefer much shorter for more leg on show (and a better tan).
But totally agree merino wool is the best!
I used to feel the same way. For some reason, in the last few years, I have gotten into socks. Colourful and Marino. To me, the 7″ sock has a more finished look. I wear them all, but prefer 7″ Marino even in the summer.