doubt capacitor

[fgytiyti7y66t]

aluminum electrolytic capacitors stored because manufacturers recommend energizing them before 2 years of storage?

Is this rule only for new, unused aluminum electrolytic capacitors? Is this rule not useful for aluminum electrolytic capacitors manufactured in the early 90s and mounted in electronic circuits?

[rikkitikkitavi]

An electrolytic from the 90ies I would if possible, start slowly if it has not been energized for a long period.

Also, depending on position and how it is abused I would replace it. They have a life expectancy.

I would inspect it thoroughly for signs of swelling. If possible, I would try to do an ESR measurement.

[klugesmith]

The OP appears to be missing a few words or sentences at the beginning.

Look up "reforming electrolytic capacitors". 
For the best chance to save a long-idle electrolytic capacitor, whether it was made in 1960 or 2020,
step 1 is careful reforming.  It doesn't hurt to log the time and leakage current (or voltage across current-limiting resistor).
When the capacitor can hold the voltage needed in its application, then you can measure its capacitance and ESR (as rikki suggested) if possible.

[fgytiyti7y66t]

Reform aluminum electrolytic capacitors is a very laborious and complex process because I would need to open all my electronic devices and unsolder all the capacitors and after the repair, resolder all the capacitors and close the device.

Currently all my electronic devices work, they were manufactured in the early 90s and early 2000s.

Manufacturers of aluminum electrolytic capacitors say to energize them within 2 years, but I don't understand. Before two years, is it not necessary to reform them? After two years, is it necessary to reform them?

For aluminum electrolytic capacitors used and manufactured in the early 90s in PCB, the dielectric and chemistry is altered and this manufacturer's rule does not work in this case because the capacitor is old?

here my house temperature storage 33-35C

[klugesmith]

>>Currently all my electronic devices work, they were manufactured in the early 90s and early 2000s.

If they work today then, as far as I know, all their capacitors are formed.
If you are planning to store the devices for years, I can't think of any preparation better than having them powered on for a few hours.
Capacitors age in other ways that can't be mitigated by reforming.

>>Manufacturers of aluminum electrolytic capacitors say to energize them within 2 years, but I don't understand. Before two years, is it not necessary to reform them? After two years, is it necessary to reform them?

It's a business contract thing.  Capacitors are completely formed when they leave the capacitor factory. If not assembled and put in service within two years, the maker doesn't want to be bothered with claims of poor quality/reliability due to lack of re-forming.