If you lose admin rights due to never using the tools, what's the big
deal?
Please note that adminship is not only about deleting images and blocking people. It's also about technical maintenance.
I have been pretty inactive with respect to writing content, or deleting stuff, etc, for a while now. I am focusing on providing external tools for the community, using the toolserver. In order to make such tools work, I have to sometimes edit a bit of javascript, or change the categorization of a license template, or adjust a system message. This means I have barely any logged admin activity in the last months, and low overall activity. But I still believe having admin privileges for me and other "technical" admins is justified, as long as it is not abused. Having to find an admin for this kind of stuff, and making sure he gets all the details right, would be a real pain for all.
I realize that I'm not up to speed with deletion policy - so before deleting anything non-obvious, I would have to read up on the policy (or leave it to someone else). Admins should be trusted to be responsible enough to know when they shouldn't use their powers (otherwise, they shouldn't be admins).
I see no point in expiring adminship.
-- Duesentrieb