Yes I replace all caps on the boards. Old caps are bad caps. Besides, the quality of caps today are much better in my opinion. I also replace every resistor and most diodes. The cost isn't really that significant. A quality vintage piece is worth it.
I have a Marantz 1060 which had lost fidelity in the phono amp. So I went ahead and replaced every board inside. The difference really is amazing.
"College graduates should not have to live out their 20s in their childhood bedrooms, staring up at fading Obama posters and wondering when they can move out and get going with life" - Paul Ryan