Speakers made from paper and cloth (as these are) are generally reliable, although almost any drivers can be blown if abused. As I mentioned above, cloth can stiffen, although that tends to be the exception rather than the rule. What these probably will need is replacement capacitors in the crossovers. If the highs seem lacking, check that the tweeters work (if you don't hear any sound from them, you can remove them from the cabinet and connect them directly to the wires coming from your receiver, as long as you keep the volume low and the time short). If they check out OK, then a recapping is probably in order.