That depends on how often you do it. If it's once a week, then it's typically 10%. I do 20% biweekly. You can do as much as you want. It's not written in stone. I just wouldn't do more than 40-50% unless there's a reason to.
But changing 10 gallons a week is fine if you want to do it. Also depends on how stocked your tank is. There's a lot of variables to take into account. Obviously if it's overstocked, then a bigger change would be recommended. Or uf your filtration isn't the best, then maybe a bigger change. But the "guideline" is 10%/week.