You have to keep the LEDs relatively cool or their lifetime decreases substantially.  That&#x27;s why most LED bulbs of reasonable intensity have a heat sink integrated into their design.  In practice, this isn&#x27;t too much of a problem when you&#x27;re designing the entire bulb (and perhaps the housing).  But it does mean you&#x27;re still stuck using incandescents as, e.g., oven light bulbs.<p>(I say &quot;stuck&quot; mostly in a design sense - the inefficiency is irrelevant in that application.  But LEDs give more shape flexibility.  I&#x27;m a fan of how they&#x27;ve been deployed in refrigerators to provide more uniform illumination, for example.)