We were somewhere around Barstow, on the edge of the desert, when the
drugs began to take hold. I remember "Dave Plowman (News)"
saying something like:

I suppose they are. But I also use NiMH for this keyboard and mouse and
keep a spare set charged ready for use. They need changing about every 6
weeks - which means the self discharge rate is miles better than 6 weeks.
The cells I use were bought from Lidl.

Can't get much lower drain than a clock or remotes.
Bog-standard NiMH cells will last six weeks in a Sky remote (in full-on
use) before the 'low battery' warning comes on and then they'll last for
ages further - or until you get fed up being nagged by the stupid nag
screen.
Similarly, b-s nimhs will last for up to six months in a small shelf
clock - and these are ancient ones I keep just for this application.
So, it seems that as long as there is *some* current drain, the ordinary
cells last much longer than just sitting idle.