filing and other deadlines that other practices do, but the need to serve generally very demanding clients and partners was still there all the time. When a partner calls you out of the blue at 3 pm on a Saturday afternoon and tells you to revise some documents and get them to him that night, you have no choice - you have to do it, even if you've made promises to your wife or kids.
And regardless of deadlines, the pressure to bill time never goes away, because hours billed and receipts collected are the only metrics that matter (as an associate anyway). So the work never really goes away - you're always either working or thinking in your mind about how you should be working.
Having said all that, I loved my experience overall and would recommend that any attorney take a big firm job if it's an option.