Recoil Spring replacement frequency

I put about 5000 rounds through my 1974 Hammerli 208 International without a single alibi. I bought it used, but it looked like it was used very little. I don’t know how many rounds the previous owner put through it. The gun shoots great. When should the recoil spring be changed? Are there any other maintenance parts that need to be updated and when?
Thank you in advance for your advice.

IMO, getting a spare recoil spring from Larry's can't hurt.  From my limited experience with worn 208 recoil springs, the spring gets a flat worn on the side from rubbing against the frame and is easy to see.  But, by then the damage has probably been done.  Also, if you haven't replaced the recoil spring, it's a good idea to do so and understand what is involved. 

There is a European website (that I can't seem to locate the link), which describes replacing that spring on a regular basis as the 'fountain of youth' for the 208.  I am paraphrasing and YMMV. A guy on www.targettalk.org described moving the barrel sightly to allow removal and replacement of the recoil spring on (older) 208 international models: http://www.targettalk.org/viewtopic.php?f=4&t=56683