I recently purchased some Assassin snails. Do they need to be acclimated? I acclimated shrimp and fish using the slow drip method in the past.
Snails are generally much more resistant to water changes than fish (and definitely shrimp).
So I would not bother to acclimate them, or definitely not for the same duration as with fish or shrimps. E.g. 15 minutes or so, just to be safe.
I bought a few a few of these a while back and just dropped them in my tank. I also transferred them from 1 tank to another, without any problems or deaths.