I had something happen a few months ago where I was playing another game and suddenly got booted out of the game and out of Origin. I couldn't log back in with my password. Then I got an email that said I had to change my password due to suspicious activity, so I thought my account had been hacked. So I did all that, got back in. Then it happened many times after, and it happened to several friends of mine too over the course of a few weeks. It was some bug with Origin (don't recall what the cause was) that was locking people out of their accounts. So needless to say, because of that, I had to change my password to something new each time I got the "suspicious activity" message in error and was locked out. So it doesn't hurt to change passwords every now and then.
On a related note, earlier this evening I saw a charge on my paypal account for something I didn't buy, but I hadn't been charged yet so I was able to cancel it before I had a mess on my hands. So either somebody has my email and plans on using it to go on a shopping spree at my expense or it was a mistake. I'm glad I caught it early and it was time to update paypal and that email's passwords too!