Quote from rocky_raccoon:
Interesting info so far... Here is what my summary is:
Calendars look like butterflies but there is a key difference. Calendars are vega positive while 'flies are vega negative. Hence they should be used in the opposite situation (low IV - go with a calendar, high IV - go with a 'fly). R/R is better with 'flies though.
Adjustments should be avoided and I totally agree with that. Adjustments may make sense only in the case of multi-month calendar (e.g. SEP/NOV) when a short leg is rolled to the next month as it gets close to the expiration.
It is better to be a directional then neutral - I agree. Moreover, I think that the preferred direction should be down since in that case a calendar spread is set to gain from directional movement and IV increase.
No individual stocks should be used as they present too much of a gap risk - that was my original statement - although someone mentioned individual stocks in their experiences.
My only concern now is the reasonable possible loss and exit rules.
If we're talking about strictly ETFs or indexes, what would be "must close" loss in a position and how probable is it? I guess I need to find some stats on that and do back testing.
Same goes for profits. If a spread gains 10%-15% in 2-3 days, close it or wait for more?