This is what I know about calendar spreads: we aim to profit from the faster time decay of the near-term option while holding a slower-decaying long option in the farther expiry. The gamma of the near-expiry option can cause issues because even a moderate move in the underlying can swing the short option’s premium a lot, and sometimes the long option doesn’t fully offset it which may lead to loss. Also, vega is higher for the longer-dated option, so if IV drops, we could lose, and if it rises, we could gain.
Plz add anything important, cautionary, or any interesting points or advise about calendar spreads that I might have missed above. @pavinjoseph @BB789 @SpacemanSpiff @niftymonk