"fret about" or "fret over"?

I worry about this and I fret about that.

So there is no point fretting about it.

I have also been fretting about it ever since.

I fret about asteroid impacts, as you might imagine, but this one doesn't worry me at all.

So don't ever fret about putting up one line posts about crossing the bedtime finish line.

He frets about what his fans think of him, and whether he will ever be able to sing again.

Demand for higher-risk currencies has been sluggish as investors fret about the possible impact of some $600 billion in expiring U.

So we are allowed to listen to Driver A fretting about a lack of front-end grip, or Driver B being told to put in a couple of super-quick laps while a rival is stopping for a tyre change.

While many scientists are fretting about the shrinking polar ice caps, and well meaning activists show images of ice bears on a lonely block of ice, it has lost the impact in the suburbs.

Cloud area blogger Gary Gross segues from fretting about a federal Bureau of Land Management press release from Colorado to questioning the existence of Minnesota's Environmental Quality Board.

Don't fret over the daily ups and downs of your stock.

In essence, we may be fretting over what was always going to occur.

We must stop fretting over the minute statistical risks of cancer from chemicals or radiation.

Though glad there was food for sale, shopper Tova Lynch was fretting over the beef selection and wondering what she would do with a mere two-pound brisket.

For one thing, America is now fretting for more than ever over the possibility of al-Qaeda again attacking their soil.