If we apply it to the human body then it doesn’t look like quite as good a diagnostic process.
Really only some capacitors get replaced on sight for me. Usually only RIFAs which are cracked. I have 40+ year old electrolytics still absolutely fine. High ESR is an almost perfect indicator of problems and it’s measurable in circuit. The reason stuff tends to get shotgunned is lack of equipment. Best bet is really to:
1. Visible inspection.
2. ESR measurement.
3. Replace anything leaking, high ESR or RIFA.
4. Power up, leave for an hour. Or replace any shorted tants when this doesn’t work.
5. Have a feel around for warm ones and replace them.
The main issue with shotgunning is cost. Secondly risk of screwing up the device entirely. You’ve all seen it, particularly that 475 I picked up at Newbury last year
The difference is, as you've shown right here, one thing: EXPERIENCE. If you don't have the experience, or have sense enough to come someplace like here or the badcaps forums and ASK for the benefit of other people's experience, then you WILL be engaging in "uneducated troubleshooting" when shotgunning, because you will not know which caps are "of a kind highly prone to failure" in YOUR particular bit of gear.
I make it a habit to look extra close at ANY duplicates of a cap I've seen visibly failed; if I find another one, I'll at least consider replacing all of that breed/value/Mfr Product Line I find. If I find any of suspicious ESR/Tan Delta, I'll usually evaluate the same. But before I even START, I'll usually try and do my homework FIRST and check in the relevant techie forums.
Also, there's a real difference in what you consider to be "shotgunning". Just how far do you take it? Very few cases do we replace EVERY GAWDDAMN CAP in a device. OTOH, I consider the usual rebuild procedure for a 24xx series PSU to be a prime example of shotgunning, but we NEVER replace those big blue soda-can axials in them.
Again... it's all a matter of EXPERIENCE; whether you're taking advantage of your own or someone else's.
That’s fine for a business but from a hobby perspective preventative maintenance is expensive!
Yes, as with most things that men do... our hobby is expensive. Limiting the available funds is part of how we keep ourselves from doing the REALLY stupid shit we would do if we had unlimited funds, free time, and no adult/female supervision.
I have no problem whatsoever killing off whole handfuls of caps if they're even slightly questionable; no matter how much they cost, my time is worth more.
Within reason, of course.
mnem