They may actually last longer than 1.8 years. Remember I proved, at least to myself, that the 2 pack of bulbs at 2 for $3.98 are the same exact bulb inside and out and yet they are rated at 4.57 years.
BTW, make no mistake, that is 4.57 years. Not 4.56 or 4.58. 
That just reminds me that I should take all of that stuff with a grain of salt 
As to my post #154 where a massive heat sink version of the 1100 Lumen bulb had the same exact lifetime as a version with no heatsink just shows that a lot of these printed specks are just a “copy and paste”
In another thread Found: $1 LED light bulbs at Dollar Tree I made a passing inference to this with this picture. 3 manufacturers of 3 different 40W equivalent bulbs, Osram, CREE and Greenlite. All three packages had the same EXACT specs.
450 Lumens
72 cents yearly operating expenses
22.8 years service life
6 watts.
That is not a coincidence, it’s “copy and paste”
