Okay kiddo, have you ever heard people saying that you should never let your phone's battery go down to 0% or charge it beyond 80-90% because it will harm your phone's battery life? Well, this is what we call the "999 phone charging myth."
But this is just a myth, which means it's not true. You see, phones and other gadgets have something called a lithium-ion battery inside them. These batteries are really clever, and they know when they are full, so they stop charging automatically. And when they get low, they also know to alert you to charge them up.
It's true that over time, a battery's ability to hold a charge will decrease, but that's just natural wear and tear. So as long as you are using your phone normally, like letting it go down to 0% and charging it up to 100%, it won't harm your battery – in fact, it might even help it!
So don't worry too much about this myth, just use your phone as normal and make sure to charge it up when it needs it.