capacitor - Does the voltage across an electrolytic cap significantly alter its lifespan?

I've heard two sides to this question: Does the voltage across an electrolytic capacitor significantly alter its lifespan?

1. Yes, it does. The rating should be 1.5x - 2.5x the expected voltage.


2. No, it doesn't - and United Chemi-Con say so themselves. (Search "(a) Operating Voltage")

I'm more inclined to believe UCC, but I've seen the 1.5x-2.5x rule applied on commercial high reliability designs too (even when the rails were never expected to exceed cap rating, for example an overvoltage protection circuit is used.) I've also seen the opposite in high reliability designs, for example one oscilloscope (which is still going after 19 years) seemed to use a combination of both.