If you don't have a dedicated gadget, separating eggs always runs the risk of a cracked yolk seeping into your egg whites. But if you use three bowls throughout the process, you'll never need to worry.
Emma Christensen at The Kitchn, like many of us, used to use two bowls, cracking the egg into one, and scooping the yolk into another. A better solution is to pour the whites from each egg into a third bowl, and keep cracking eggs into the newly emptied one. That way, if a yolk cracks, it will only ruin one egg, instead of all the eggs you cracked before it. It does create a little more clean up, but that's a small price to pay for perfect egg whites.
This is the kind of tip that's obvious in hindsight, but worth keeping in the back of your mind whenever you need to separate eggs for a recipe.
Why You Should Use 3 Bowls When Separating Eggs [The Kitchn]