There is no requirement that pickup runs 100% of the time. I don't know where you got this ill-conceived idea from.
Opps.After my very first postfix install (last year), on a new server with no email traffic, I did a "postfix start" and noticed that only "master", "qmgr" and "pickup" appeared in the process table, so I assumed that those 3 processes were always "running" in postfix.
So, there is no need to monitor "pickup", right? Thanks a lot :-) -- Santiago Romero