For fresh string I have probably 100+ Chaos 422 and some 622, less than 100 YYN highlights, less than 100 white cotton, 10 CLYW glow, 10 slim white Kitty, 10 normal black Kitty, 10 Dragons, 5ish white YYSL Venom and a few assorted strings. I wanted the 2 types of Kitty and the glow just to try (so far I’m very unlikely to buy again), YYSL is my go to string and I don’t really see that changing. At this point I’m moderately confident that I prefer Venom to Type X. I had a ton of extra random strings (stuff people have sent me in deals, my own old GString and other stuff), every time I sold/traded a yoyo I tried including 2-3 fresh random strings until I got rid of all of it.
I use the Chaos 422 in my small bearing throws, I use the Venom in all my new/favorite throws that will get the most play. Once a YYSL is worn enough that I decide it’s time to change I’ll either throw it away or frequently put it on a yoyo I don’t throw much that has a highlight. If I don’t have any used but not too used YYSL then I put highlights on the yoyos I don’t throw much if I happen to pick one up and decide it’s time for a new string.
Using YYSL I’m not sure I’ve ever used more than 2 strings in a week but I also tend to throw at least a couple different yoyos. I’m not much of a string changer, I generally play them until I feel like the tension changes too quickly and they’re fuzzy enough that it seems like they snag on the response unexpectedly. For highlights it’s not unusual for me to go on a kick where I throw a yoyo for an hour and replace the string. They’re cheap, they work great but they get fuzzy and gross fast.