When do I use a for loop and when do I use a while loop in the JavaScript challenges?

All for loops can be written as while loops, and vice-versa. Just use whichever loop seems more appropriate to the task at hand.

In general, you should use a for loop when you know how many times the loop should run. If you want the loop to break based on a condition other than the number of times it runs, you should use a while loop.