Running 10.7.5 on a 2011 MBA 13 with the 128gb SSD. I sometimes get a running out of disc warning, and Omnidiscsweeper shows upto 15-20gb in var/vm/sleepimage. Did a bit of searching and found that a lot of this space is released by restarting. Restarted now and found 15gb released, but still 4gb is taken by sleepimage. I thought that Macs NEVER need to be restarted? Anything wrong that I am doing?