Check the shutter actuations. In Bridge right-click a recent shot you took, go to "File info..." then "Advanced" then "Schema (http://ns.adobe.com/exif/1.0/aux/)
" then look for "ImageNumber". This might be different for Canon. Search "Find 60D shutter actuations" or something.
Anyway, this number is the number of shots taken with the camera in its lifetime. Shutters are rated to like 100,000 (check your camera's spec sheet) so if it's under half of this don't worry.