If you shoot wide open and want accurate focus, focus and recompose will result in OOF pictures, especially with MF. This is because the plane of focus is... a plane, not (part of) a hemisphere. Either use manual focus or Live View (if available).
You may get away with recomposing with some subjects, especially if the recomposing is minor. Also, if you stop down and/or don't need tack sharp pics, you'll do fine with recompose.