Another data point…
I just replaced an Energizer lithium cell that I installed on 19 March 2008. The logger runs full-time, taking data points every few minutes.
That’s nigh onto two years of life!
I must conclude the battery life problems mentioned there (admittedly, in a different logger) were due to craptastic Renata cells, rather than the Hobo logger itself.
Lesson learned…
The Smell of Molten Projects in the Morning 