[Fisherdude]

Would we still be asking this question if a radio made in 1935 had been repaired in 1955 with all new capacitors?

Unless the radio is a true, irreplaceable rarity, like Sandy listed, then most collectors feel that repairs done to make a radio function correctly, as it did when it was new, do not reduce the value. Instead, those repairs keep the radio alive!

As long as it's not a "mod". That's different. That makes the radio different than it was originally.

There are three different levels of recapping:

1. Replace the cap with an exact, NOS, identical unit to the one that's in there, or else leave the old one untouched. In other words, if you can't find an original replacement, you don't play the radio. Even if you do find an NOS original, it's going to be 40-50-60 years old, so playing the radio at all would still entail big risk. This choice is usually only for museum quality radios.

2. "Restuff" the original cap with modern guts, but keeping the original outer paper tube/can for appearance's sake. Best of both worlds, if you really like to work with your hands! Can be a real challenge to find a new cap that fits in the old tube/can. Remelting the old wax, or adding new wax, and pouring it into that little paper tube requires a steady hand!

3. Replace the original capacitor with a new one. Sometimes when this is done the original is left in place, again just for appearance's sake, with the new one put under the chassis. Leaving the old cap in place is usually only done if the original is a can type on top of the chassis. Tubulars underneath usually get pulled and tossed. Especially if it's already tight for room underneath. Personal choice.

Number 3 is probably done in 90% of all restorations.
Dive in and have some fun!
Clay