I took profits at 15%+ OR continuously rolled (which cost a lot of commissions). So if SPY straddle was at 165 and SPY hit 166.05 I'd roll the straddle to 166. Some weeks I rolled several times which may have killed the trade.
Edit: I will run Aug to Nov and see how it does
If you have specific parameters you'd wish me to include, let me know.
PS I rolled the straddle when SPY was +1/-1 not at EOD.