if you're not connected to the internet, i would say yes. but since you posted here, you are using the internet
think of it this way, installing win 7 is like building a home.. as time passes by, thieves would want to go inside your home especially if you have valuable things inside it.. would you leave your home as it is or do you want to have a safe home by making sure you have additional locks and anti-theft devices?
updates are just in kbs most of the time so i would download them if i were you
i know this is a very basic logic but still works right? plus it is easily understandable