looping question

It's good to practice all the control structures to where you know them and how to use them well so that when you later face a new problem you won't be thinking in limited terms.

IIRC a while loop is actually a tiny bit faster than a for-next.

// initialize values then
while ( conditions checked in order to run, may not run at all, kind of an "if loop")
{
// vary values
}

do // runs at least once every time
{
// vary values
}
while ( conditions checked in order to keep looping );

for ( initialize conditions; check to run; change every time )
{
}

You can also use labels and goto but that's a bad idea.

And not to forget how to stop an Arduino:
while ( 1 );