Lens - Sharpness

I've been struggling for a wee while now trying to understand why my images have not been sharp. I've changed to TV to ensure I keep my shutter speed high to avoid camera shake. Tried different ways of focusing. Still wasn't ok. Finally decided to get my lens checked. Eureka! Problem with my lens. Canon have replaced power diaphragm unit, image stabiliser unit, rear lens unit, adjusted optical unit set to standard.  No excuse now for unsharp images.