I count in 3's because that's how I was taught to count newspapers when I was a paper boy. I didn't really question it but you're quite right that it's just as

I count in 3's because that's how I was taught to count newspapers when I was a paper boy. I didn't really question it but you're quite right that it's just as easy to see 3 items as 2, and it's faster. You just have to get used to the sequence but that's much easier than remembering all the multiples of 3. Our brains are great at remembering the next item in a sequence even if we can't randomly access them very well.