He's Made a 360-degree Turn in His Life
Except if he's right back where he started, that's probably not what you mean. Degrees aren't only a way to measure temperature and angles; they're also clichés writers and sportscasters use to describe everything from major life changes to spinning slam dunks on the basketball court. The problem is that these terms are regularly misused.
A complete circle is 360 degrees. So, if you want to describe someone who has "come full circle," you might say he has made a 360-degree turn. A half circle, meanwhile, is 180 degrees. This is the phrase one might use to describe a complete change from one extreme to another. A shy wallflower that busts out of his shell and becomes an extrovert overnight might be said to have made a 180-degree change. If he later reverts to his shrinking violet ways, he has gone 360 degrees, landing back in the same position he started from [source: Gray-Grant].