It seems like every year in this job there is something else that "you just do now". It may not be in the same sense of turning 40, but it's not all that different either.
The teaching and research goals are fairly obvious and then there's the service. I don't really mean departmental and university service - I try and keep those as close to the acceptable threshold as possible - but research service.
A little while back I organized a local research conference for 120 people. Why? Because that's what you do now. I review a lot of grants and papers and put my name up for review panels at NSF for a similar reason, although these help me as well.
I'm now in my forth year and facing a new task: Associate Editor. I've been asked to serve as AE by an incoming editor of an important journal in my field and even though I need the extra work like a kick in the teeth, it's one of those things that you do now.
I have no idea how this is going to go, but hopefully I won't need ten Aleve a day.