Yes indeed, if one can switch trades on right time, nothing better than that.
One of my colleague was asking me to keep an eye on the amount of premium in Nifty Futures & Bank Nifty futures till 3:30 PM today. He claims that if the Future Premiums are quite high (just before monthly expiry), then one should SHORT or buy ITM index Puts for tomorrow. Because most probably the market will tank. Similarly, if there is no premium or if the Futures are in Discount (one day before expiry) then one can actually go forward and BUY ITM Calls or Futures. This comes to me as a surprise. How true is this?? He claims that one can make huge profit by doing this on expiry day. Does this strategy ever work?? I personally believe that it can be very dangerous.