Quote from bone:
Looking at my statements for this year, I can see that my average holding timeframe for Eurodollar Calendar Spreads (Z1-Z2 particularly) was 14 trading days.
A Nymex or ICE crack spread might be 30 minutes up to three hours. As of this morning, the August RBOB Crack had a 202 tic average twenty day trading range and a twenty day hisorical volatility of 93 %. Obviously you want to trade that beast differently than a Eurodollar Calendar that has a seven tic daily trading range.
For me, at least, the volatility and trading range of the particular spread determines the holding period. We set profit targets and stop-loss levels at the time of entry.
As an example, I bought the U1-Z1 Heating Oil Calendar Spread last Wednesday morning on July 13 and it is marking up nicely but we are still a fair bit away from the target levels.