I'm wondering what the expected lifetime is for electrolytic
capacitors in recent years. I'm sure temperature and operating
voltage play a role.

The reason I'm asking is that I recently replaced the electrolytic
capacitors in the power supply of a 23-year-old Fluke signal generator
I own. One of them was "bulging" so I replaced all the large
electrolytics in the supply, and for good measure, the tantalum ones
as well. The supply voltages are now cleaner.

There are a number of other electrolytics on the various circuit
boards in the synthesizer. I've already replaced a few of them as a
precaution, e.g. 16V, 220uF caps across +/-15V supply lines. However,
all the others are operating well below there rated voltage, and I'm
wondering if it's worth replacing them while I have the synthesizer
apart.

-Dave