I’ve been playing with them for more than 20 years now so I have a lot (like 100+ in a storage crate in my closet). But I only use one these days. There are different shaped yo-yos for different styles of yo-yoing. For instance the yo-yo in this video couldn’t be used for “loop the loop” tricks, because a butterfly shaped yo-yo won’t flip between loops like a rounded one will (the flip over adds stability and control allowing for continuous loops), but a looping yo-yo couldn’t do these tricks in this video easily, as they don’t spin as long. I personally prefer and stick to this style of yo-yoing so I only need one good yo-yo for that purpose :) thanks for asking!