I agree with bluepilot.
If you can eliminate electrolytic capacitors where possible. It is not too difficult in valve gear now as often there are many poly caps of the same capacity and voltage that can be used for re-stuffing.
I have now gone to other types of capacitors to replace the filter electros in my valve gear restorations, they are shown at the end of this thread:
https://www.vintage-radio.net/forum/...=140570&page=2
The problem remains though in vintage transistorized equipment where the common capacitances can be over 30 to 50uF, often into the 100's or 1000's of microfarads and there is no room to fit other capacitors. In this case my practice is now to fit Tantalums, preferably mil grade for lower range values and I remain forced into an electrolytics for the high values, but I always strive for the higher temp rated parts.
In all my home design projects now I avoid electros by design if possible.
There is a field where electronic designers felt obliged to avoid electrolytics. This was in the design of electronic modules for under the bonnet use in cars (and of course in spacecraft).
If you look at vintage circuits created by companies like Motorola in the 60's and 70's, for various ignition and charging circuits there is not an electro in sight.
One company tried to subscribe to this view in the 70's and made an add on CDI unit, the Delta 10. Their design succeeded in eliminating nearly every electro except one, they had to have one high capacity filter cap. These units are nearly always still working because of this. They used a special 125 degC rated part (photo attached). It is interesting today that these caps are nearly always perfect over 40 years on and they are the only electrolytic cap I'm fond of.
These electros are made by Rifa and last much longer than conventional electros and they also have much better physical seals. They are still available last time I used one, you can nearly 100% guarantee they wont fail or leak over your pcb. They are the only electroltic cap that I trust now.
What this really shows is that it is possible to make good electrolytics, but they cost a lot more $, that Rifa cap is not cheap. So we are looking at a situation where electros are being made
down to a price, not
up to a standard. With all the different competing companies making them, trying to undercut each other on price, it is not really surprising that there are so many poor quality electros around. A simple case of you get what you pay for perhaps.