In addition to batching email, Linkedin, etc.) once a month. Usually less. Almost always as a matter of obligation to friends who directly request it. Once a month is actually more frequent than I'd like, but it falls in nicely with other things I do once a month like balance my finances, clean house (hypothetically - if I had a stable house to clean; I used to clean my room roughly this often in the dorms). That kind of thing.

For me, things like social networking sites can be a handy tool - or a time-sucking addiction. Scheduling checks once a month is the way I keep from becoming the latter.

Sure, getting who-hooked-up-with-whom notifications in your feed reader makes the gossip chain faster, but is it actually more convenient? Did you really need to know that right now, or can you just look it up later if you're curious who so-and-so is currently going out with? (Do you really need facebook to know who your friends are going out with, or can you - y'know - ask them? As part of a conversation?)

Do you really need to interrupt your paper-writing to pop in and approve that new friend request 30 seconds after it was made, or can you batch-process them all at once after dinner? After dinner next week? After dinner next month? (Is someone really going to get upset with you for ignoring their friend request for a few days? If they do, what does that say about their priorities?)

Being addicted to social networking sites is like staring at your telephone all day just because someone might call. Might as well do something else and let it sit in your pocket, working for you in the background. If someone calls, you'll hear the ring and can decide whether to let it interrupt you. If you need to make a call, you know where to find it.

I have accounts on social networking sites so my friends can find me and I can find them when other modes of communication have failed. That's the reason I use them, and for that usage, a few minutes once a month is more than sufficient.