So, i master all of the tricks on the yye list. (not seasic) and si far i have only used the yye polly strings. Do i need something else? And what would yourecomend for what kind of tricks. I am only doing 1a and some 4 and 5a. Nice if you could tell me your experience 
Actually YYE polyester is perfect to learn 5a 4a and 1a on.
I’ve tried Kitty string, I love it it’s softer and it’s longer that normal YYE string. If you get kitty string, (comes in 100 packs) you will have to tie your own knot for your finger. Here’s how you do that:
Also there are many other brands of strings out there. Toxic strings, G strings, etc…
You can grab ten packs of those in the store to test them out to see if you like them. (Kitty String too) Different strings can do better for slack suicides etc…
Hope I helped!
Whatever string works for you, thats what works! No need to change what string you use just because you’re “advanced”
I’ve seen world champions use stock bundle string, from online stores, to win the world championship. Why shouldn’t you use it?
Any string will work. As long as you like it.
what strings are the bests for slacks? i really like doing it and i am making up some cool whip combos 
mayde they can halp me improve them? 
If you want to experiment, buy a bunch of 5-10 packs of various kinds of string and see what works best for you. There is no best answer that suits everyone. Some people like Kitty string, some people like YYE bulk string, YoYoStringLab, Toxic, and so many others. Some people like to match the string to the yoyo based on what they feel provided the best performance.
There’s no “right” and there’s no “best”. There’s only what you discover is best and right for you and that yoyo. After that, the rest is meaningless.
Have fun with the string!
Thanks. I’ll try
Kitty string is your best bet. Its so soft on the hands and long lasting. And only like $15 for 100