For me, on average, I touch around 300-500 pieces a month, depending on how much stuff has come in, what projects the department is working on, and how much non-tallied work I do that month.
Last month I assigned new call numbers to 932 items. And changed call numbers for another 40-some more.
And May is quickly shaping up to be busier. This year the library has the largest materials budget it's ever had, and some of the departments got a bit behind in spending, so they're making up by spending it all now. (Our fiscal year ends June, and stuff has to be ordered in time to arrive by June 30 to be counted against this fiscal year.)
While it's normal for my candle to be burning at both ends, I think it's currently being dangled over an open flame...
Feudalism: Serf & Turf