Talk:Time Stop/@comment-86.253.189.235-20200208220655/@comment-8506165-20200216141203

That's... a pretty contrived example. And not entirely accurate. Time Stop has the same cast time as Improved Alacrity so it's just as likely to be interrupted by the enemy. Spell Immunity insta-casts with Robe of Vecna and Amulet of Power so you can actually just throw it up immediately if you see Imprisonment flying towards you upon finishing your Improved Alacrity cast. And even if Imprisonment actually landed on you before you finished casting Improved Alacrity, the relatively lengthy animation has to complete before you're actually imprisoned so you still have time to empty out basically all your low-level spells onto the enemy before the Imprisonment lands, which will probably kill or severely damage them.

It's also odd that in the time it took you to cast IA, they managed to cast Imprisonment, which requires them to be next to you and has a cast time of 9 when your Improved Alacrity has a cast time of 4 with Robe of Vecna and Amulet of Power.

Generally OP is right; if you're only casting spells that have a casting time of 0 with Robe of Vecna/Amulet of Power then the Time Stop is actually rarely necessary because you can just spam them all out in less than half a second anyway. But if you're looking to cast several Abi-Dalzim's or Incendiary Clouds at the enemy then in that case throwing Time Stop up before IA to allow you to throw them all simultaneously and uninterruptibly is better. The other case it might be useful is if you'll need to move around between 0 cast time spellcasts, or if you're fighting fast enemies that might move out of your AoEs in the time it takes the projectile to travel.