Most will tell you that a boat should replace it's standing rigging after 20 years. Key is the environment in which the boat is used - lots of use in salt water may require more frequent replacement. Use in temperature extremes where there are of freeze/thaw cycles will stress swages too. You have to go aloft look at the hardware carefully every year and make a decision. But I think that given the cost of re-rigging a boat, most people don't do it. But 20 year old rigging is not anywhere near a death sentence, IMO. I'll probably get jumped on for saying it, but very few recreational rigs come down from failed fittings under conditions in which most of us sail. Rigs have come down, but there are usually other factors involved. I worry far more about hose failure than rig failure.
We have a 1984 boat with original rigging and I have total confidence in the rig. With that said, we'll be replacing ours (finally) next summer. I plan to have the upper ends swaged by a rigger and I'll do the lower ends myself with StaLoc fittings. Easier that way.