In message , Graham.
wrote

It appears to me that if it's quoted in hours, it means continuous use
but if it's quoted in years it's some unspecified daily use.
I have even seen both figures on the same lamp without any explanation
why mathematically they didn't correlate.


I've had two blow recently. Both went on switch on. I'm sure that the
electronics in some of these bulbs is not fit for purpose and the
claimed life is the continuous life, if you never switch them off.

--
Alan
news2009 {at} admac {dot} myzen {dot} co {dot} uk