A lot depends on the circuit. Filter caps should be the same or slightly higher in value then originals. Higher values reduce hum but too large is hard on a rectifier tube.
Larger coupling caps will increase low frequency response of a radio. Very large may cause a radio to oscillate at low frequency.
Bypass caps can be increased without causing a problem. Caps from screen to ground can be 10 times greater in value.
Caps on a signal line to ground shouldn't be increased or high frequency response of a radio will be reduced.
Don't change values of caps in an oscillator circuit that effect frequency.
Norm
:gonna recap the philco 80 now that I have the proper values THANKS TO NORM FOR DIRECTING ME TO "most often needed radio diagrams webpage"...Question is how close do these caps have to be. I'm guessing if the cap is to ground then its a filter cap(how far off can we go here, and not make a difference). Oscillator caps, coupling caps or whatever else kind of cap too..just dont wanna screw anything up here