Do you guys just replace every single cap on every old board? Or do you measure them all in circuit? Or do you only do visual inspections?

What is the right way...

I want to preserve the stuff i have but i do not see myself recapping everything just to be safe (and maybe kill a few in the process).
I do replace them on boards that have bulging ones.

For me it depends on how many are they, how do they look and what brand they are from. In the case of my WD hdd, I know that they might not be all dead, but I wanted to make sure that they won't cause any issue anymore. Having 2 shorted caps and one that explodes out of 12 is a huge percentage of loss !

I also recapped COMPLETELY the psu with brand new caps because the pc was unstable. But when something old has no problem whatsoever and no bulgy caps, I don't really mind. But when it comes to stability, even though they look right, I tend to change all of them. Capacitors are probably the easiest components to remove (except when they are surface mounted but even in that case, they aren't too hard to remove) in comparison to some other components (at the moment I'm trying to clean and repair the rtc/floppy controller/serial/parallel/game expansion card from my 8088 that do not work right because the battery leaked, and so I have to desolder corroded chips and put new ones back in there. But I think I've identified the problem : the dip switch box seem to have a problem, switches doesn't move right and when they are set to "on", the circuit is still open))