Helpful advice on whether to buy old penn rods/reels?

I see many all the time on craigslist, at yard sales...etc I have looked them up and old penn reels and rods are said to be of the best, but what do i look for when buying an older rod/reel? Will older Penn's still be able to catch saltwater fish like striper? Just don't know much about buying older fishing gear, if you can help , i'd appreciate it.