How to ensure a long-living diode?

Hey guys, quick question about laser diode life expectancy:
For the same amount of power output per time, is it Better to run a diode at the high end of what it's rated at for short bursts or to reduce the current available? Should it make any appreciable difference?
(PWM vs. variable current)

Running diodes closer to there max mA will shorten it's lifespan. More specific information would allow other members to tell you the exact mA "range" to run it at.

Thanks for the response!
so just to confirm... with the trade-off of shorter total time on (pwm) vs. lower peak current (current regulation), current regulation is pretty much always the better way?

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Questions might get technical so I've started a thread in the power supply section:
http://laserpointerforums.com/f67/question-about-typical-overvoltage-allowance-61178.html

Also, keeping diodes cool is a must for long life. For higher power diodes, I direct press them into a heatsink, totally bypassing the aixiz module.

thanks for the tip, I'm hoping my peltier arrives soon!
Does higher temp shorten diode life appreciably, even at moderate levels? ie, should I keep the thing at 25C vs. 60C?

if possible:
* Derate your diode's current specs. If an LED maxes out at 20ma, power it at no more than 12-15ma. Discourage yourself for the max power mods by bridging or otherwise bypassing designed safety features
* Reduce the duty cycle, bursts over continuous usage
* Store it away from humidity
* Reduce lateral trauma, such as tapping it or banging it around. lasers have cases for a reason, use it!
* Use rubbing alcohol to clean it if needed be, do not use solvents
* Derate its operating temperature, even if Tj(max) = 100C for example, Tj should not attain a temperature so high that you'll have trouble holding (~50C)

While not an experienced engineer, the nature of diode junctions allows slightly improved performance operating under PWM as opposed to continuous constant current. However, my level of expertise peaks is limited to LEDs. Laser diodes may operate differently.