Hey Jenc,
I'd say for some adult folks 6 months would be a marathon! I've seen some blogs implode at the 30 day mark.
Its important to keep a good track of the blogs you've done link exchanges with for this reason. I use
www.bloglines.com
that way I can see who has updated when
If its been too long, they get a gentle nudge. if its still been really long they get the axe
