I see from the replies: most people mostly use left Shift, because the right one is too far away.
That’s really bad for users of ISO keyboards, because then the left Shift is also far away!
My solution to the latter problem was to use CAPS as an additional left Shift key. (Additional because of muscle memory to press left Shift+Ctrl with the same finger in many shortcuts.)
And there’s also a super elegant solution for the right side, especially if your keyboard happens to be programmable:
This key arrangement is an idea of the Colemak community, but it works with any lettering, including classic qwerty. It not only makes the Shift keys both equally easy to reach, but makes the whole keyboard more ergonomic.
And I even did this mod to my laptop keyboard, the one I showed in my intro post: The man with the two thumbs
Anyway, if you want to try this and don’t have a programmable keyboard (and happen to use Windows), you can grab my custom “Microsoft Keyboard Layout” here: GitHub - matey-jack/wide-ergonomic-keyboard-layouts: Type faster and more comfortably, just by changing your keyboard layout. · GitHub
I used this myself for many years before switching to a programmable keyboard. (Although I used a German-alphabet variant which isn’t in that repo.) Let me know if you should try this and it works for you. 
Today, I use a split ortho keyboard and still shift with my pinkies, but use the “caps position” (outside home-row) on both sides.
I’ve been in the keymap modding community for so long, no wonder that my first post mentions a keymap mod 