This depends on where you are in your breastfeeding journey and your overall goals. In the first few weeks when babies need to be fed in the middle of the night you will want to pump, even if you get the occasional long stretch of sleep.You will want to pump until you are confident that your twins no longer need to wake and eat at night. You will also want to make sure you have enough time during the day to pump if you plan on exclusively breastfeeding your twins. It stinks to have to wake up at night, but if you need to fit in extra times it might be necessary.