That's awesome. The only part of your radio that you need to worry about is the vibrator - that's a device that has a contact that vibrates at high speed, it essentially helps generate a small amount of high-voltage AC (gets converted to DC) for the plates of the tubes. It's a mechanical device, so will wear out, but you're probably good for a long time at this point. But if it just quits one day, suspect that part. Certain tubes are quite valuable, mostly things like higher power audio amps and certain preamps. But for the most part, they're 3-5$ each, or less. I picked up a whole case of NIB tubes that should keep everything I have running for the rest of my life for under a bill.