THEN DO IT AGAIN SATURDAY MORNING BEFORE YOU LEAVE JUST TO MAKE SURE
Seriously, there was a MASSIVE Left 4 Dead 1/2 update the other day, and quite a large TF2 one last week, as well as a couple of small CSS ones. I cannot urge the importance of updating your steam games before you come to respawn!
Steam client updates aren't too big an issue for me, as I can just plug my phone into my PC and use it as a modem to update (which I did last Respawn).
As for the games mentioned, I don't play any of those at Respawn so it's not an issue here either.