[tau255]

Light fixtures were designed for incandescent bulbs. Even with advent of fluorescent bulbs and now LED based bulbs little has changed with how light fixtures are made. Old style tungsten bulbs had no problem with high temperature, fixtures trapped heat - hot air rises up and is kept inside. Components of LED bulbs like electrolytic capacitors have known life expectancy based on ambient temperature, even high temperature ones (105degC series) degrade fast when in such conditions.

Another problem is that manufacturers overdrive components. To make bulbs cheaper they just use few more mA of current, that makes LEDs run hotter, more smoothing is needed and caps get hammered by switch mode power supplies.

Without changing light fixtures to be open, allowing circulation of air nothing really can be done for standard e27/bayonet bulbs. I have personally experienced this and had clearly seen the huge difference in LED bulb lifetime between light fixture - glass globe with hole in the bottom (no air vents at the top) and another one that was just a bowl with open top. Never had to change a bulb in second one versus 5-6 changes in globe one.

[citrin_ru]

Heat is not the only problem, I had to replace once a year even 5 Wt LED lamps which are barely warm. I guess LED drivers (one cannot connect LED directly to 230V) are unreliable and fail long before the LED itself.

[xxs]

realistically, running LEDs over 60C spells their death. I've routinely seen 5730 alike LEDs overdriven by more than 40mA (not just few).

[convolvatron]

I totally agree that if run them cool enough they last forever.

but I had some bridgelux 10W that I just threw in some copper tubes on an aluminum slug with a minor affordance for cooling (some slots cut in the Al to promote convection). These ran at 80C and lasted for >5 yr at at least 80% brightness. and still the primary failure mode was the little meanwell dc/dc converters playing thermal runaway. and that whole assembly cost $10

it just has to be penny pinching at the end of the day.