Of course, an electrolytic capacitor stored at the drawer can survive
longer than 7000 hours. 

When in operation is that it suffers all possible torture. A big torture
is temperature, so, strategies are in order to locate the capacitor away
from heat sinks, transformers, and so on.  

If your power supply has a blower, make sure the caps are in direct hit
with the air flow *BEFORE* the air gets warm from heat sinks and other
hot components. 

Imagine two 10,000 µF capacitors rated for 16V, one is working with 15V,
another with only 3V, which one do you think is receiving more torture
and could get early problems?  The one with 15V for sure.  

Using electronic components at marginal values is only good for fuses,
and this is an interesting point. It is common to find power supplies
that consume 1 Amp at the output with a protection fuse of 1.5 or even
2A, since nobody wants that fuse to blow without any reason, isn't it? 
But then, in the same power supply you can find a 10V capacitor
filtering 9Vdc... or even a LM317 regulator supplying 1.4A, it means,
everything is wrong, right?  To work at 9Vdc, the capacitor should stand
minimum 16V and the regulator should stand at least twice the output
current.

Chances are that installing a 50Vdc capacitor to filter 9Vdc output will
make this capacitor lasting longer than the regulator, the power
transformer, the wires, the metal case, and so on.

According to your numbers, 7000 hours is barely 10 months of continuous
operation.  I have some electronic devices around that are powered
continuously for more than 10 years... it is more than 86 thousand
hours...

Wagner


Roland Andrag wrote:
> 
> Hello Everyone,
> 
> I have just (with somewhat of a shock) found out that electrolytic caps are
> rated for only 2000 to 7000 hours of operation.  These ratings seem to be at
> high temperatures, but nonetheless they make me feel very uncomfortable
> about using them.  Is this some unspoken rule that somehow passed me by?
> 
> I would like to hear some comments on what caps are usually used in
> differenent situations..
> 
> Thanks
>  Roland