As part of the announcement of Facebook's new "trusted friends" feature (which lets you choose up to five friends to have access to your account), the company said that .06% of logins are compromised every day. That's unauthorized people trying to log in to an account that isn't theirs. That works out to 600,000 attempted hacks every day or seven per second.
Besides the trusted friend thing, Facebook is offering an app password feature. So if you want to use an app, you can establish a different password than the one you use on Facebook. That way, you're not giving the app maker access to your Facebook login.