With a single machine there's about a $2.25 difference per week at the current BTC-USD rate. Maybe worth it if I get more machines running.
I ran it also if I ran it during the very expensive portion of the peak time and I would lose $.25 per week there. So, I could probably talk myself into giving the pool that hash and not stop it. But I'd still be saving using the peak/off-peak instead of just the straight cost.
I have no idea how to factor wear and tear of the miner, but it would seem that allowing the system to cool down then warm up every day may have an impact on the chips physically. It may make them last longer or it may cause expansion / contraction issues over time. Something to consider - but I have no knowledge which way is which. Mine runs 24x7 and (knock wood) has not had an issue for 9 months now.