I try not to mine at 0, but occasionally do when my rig is rented out.  I'd had a rather effective strategy with the longer shifts of compensating for that by throwing a lot more effort at the pool to make up for times when I was at 0, with that extra work pulling in enough to cover the cost plus a little extra.  Now, with the shorter shifts, that's more of a gamble.  If you put a lot of work into an unlucky period, not being able to sustain it means it will go unpaid (conversely, putting in a lot of extra work just before a lucky period would be freaking awesome).

Here's an example.  We hit one block when my dance card was partially filled at 12TH.  But now, it's cleared itself and I'm back down to .9.

http://i.imgur.com/3GKCHEJl.png