Early assignment isn't going to be an issue unless you're position is VERY deep ITM or there's not much time remaining and the ITM option is trading near parity. Long before that you should have been taking defensive steps (adjusting or closing).Quote from xtksystems:
One thought though was always the SPX vs SPY debate.. I like SPX better because my vertical could go deep ITM and I wouldnt have to worry about any exorcisms and simply close it out any time I chose or ride it for the bounce back. (I'm not worried about max loss on a vertical spread)