It is recommended procedure to replace the rockers that are associated with the worn cam lobe. The related rockers become scored when the lobes wear.
There is a test that can be performed to determine whether or not the elements (lifters) should be replaced. Its quite simple. I wouldn't recommend just replacing them on a whim. This is something that can be performed at any time.
You sound as if you are reasonalbly mechanically inclined. If you are completely comfortable with doing a valve job go for it. The cam and rockers are quite simple to do and can be done at any point. Everybody here is great help! The digital camera is a great suggestion. Good luck!
92 Volvo 740 Wagon aka "Mutt mover"