I would say over ten years I had somebody tell me that it would probably still work,but I'm concerned about doing major damage to the unit
Right now it just needs new fuses and some minor parts
These are nice receivers. I spent nearly 4 years behind a bank of at least 4 and sometimes 6 of them. If you are not technically inclined, I would not power the unit up to test it. Although it is not as old as the pre-WWII Hallicrafters I like to work on, it is always best to power up an old tube receiver slowly with a variac (variable voltage source)if it has not been energized for a long time. I have seen many old receivers with blown RF coils caused by a short circuit after someone powered them up to see if the radio would play.