I read the white paper. The capacitors discussed are capacitors in UPS power supplies. They discuss the modificaion of the aluminum by power, they do not discuss the presence or absence of water. At the end a conclusion is reached that DC alumimum foil electrolytic capacitors rated 1000 to 12000 service should be replaced after 45000 to 50000 hours service, which is expected to be powered up 100% of the time..
This doesnlt relate to consumer grade audio equipment IMHO. No mention is made of the tendency of the water in the cap to evaporate out the fiber plug and elastomer seal even when sitting around un-powered. I've had consumer grade caps go to 40% of deliverable power in 7 years of 2000 hours a year service (sprague atomlytics from 1970) I had one cap I install run two hours, sit on the shelf 25 years until I bought new output tubes, run 2 more hours, then leak all over and blow the fuse (CDE cardboard tube multi gang cap bought 1985). Many purchasers of old organs on organforum buy one that hasn't been used in years, maybe 40 hours use since purchase, it works a week then goes silent or blows the fuse.
As the Allen S100 amp Sangamo mains caps "never fail" according to an organ repairman in Arkansas, and ours in Jeffersonville did after 35 years service, some caps are sealed better than others. A repairman in North Carolina on organforum says the sardine can crimp seal 2-4 uf caps in 1945-55 hammond tone cabinet amps read fine on ESR and capacitance at 50-55 years of age. He also says the "green CDE" epoxy sealed caps in some guitar amps are the same. So IMHO sealant has a lot to do with years life. Don't buy 500 hour service caps IMHO. I don't know if the 3000 to 10000 hour rated service life caps I'm installing now will last 35 year at low usage/year, but I hope to be here to find out.
There is another number, shelf life. I think this has to do with whether caps can be installed unpowered before they unform and might short at initial power up. I check all caps with an ohmmeter before I install them, which reforms them somewhat with 2 VDC.
And the people that think reforming is all you have to do to old caps, could also believe in fairies in the garden. Try checking the air pressure, then driving on 25 year old tires, for a reality check. 25 year old rubber is ****, and if the caps builder used that **** to seal your cap, the cap is pressure sealed with dirt after some years. That CDE cap blew with 4 hours service life on it, and 25 years.
Unless the part number is written on the cap (usually not) and the original datasheet from the year of purchase has been saved, you can't tell with an ESR meter whether the sealant was gum rubber, tar. buna N rubber , silicon rubber, epoxy. You can spot the steel crimp of 1945. End plugs can be fiberboard alumimum or steel. A better guide is, how do the caps purchased by this manufacturer generally hold up? In my experience, dynaco OEM and TV repair supply caps, 7 years @ 2000 hours power per year (hot location). Hammond and Wurlitzer organs built 1955-1980, 15-20 years, more in air conditioned houses and cool environments (Kent UK) . Allen & Rodgers organs, 30-50 years, the lower number in non 100% air conditioned churches in warm enviroments (as here). Peavey amps (2 samples), 15-20 years with weekend bar band use. (A 1998 amp is blowing the fuse unless powered up several times). Computer accessories and TV remotes, 5 years or less, Apex is the worst. Dell computer boards (intel) seem to last longer than gigabyte, and this Phillips CRT monitor is 15 years old, many lesser CRT monitors blew the fuse after 3 years. In motor drives, Semi brand motor drives leaked out the caps slime and blew the breaker after 3-5 years (CDE flat pack caps MLPE1192 to be specific). Semi drives are no longer used by that conveyor builder,. Woodman and Allen Bradley motor drives can go 10 years 24 hours/day 6 days a week in 130 degree F oven motor compartments, before blowing the end out the caps (nichicons were in woodman drives, AB drive caps are marked with their brand).