One of the jobs that we received recently at R3 Data Recovery Hospital was in such a terrible state the chances of recovery was almost zero to begin with. The customer had attempted to open the drive himself before the delivery to the lab had been made. Without a clean room, required knowledge and proper instruments to do so, this is always a terrible idea.
This particular job had the all evident signs of everything that could go wrong in the attempt of opening it yourself. If the customer had refrained from trying this and sent in the drive to R3 untampered with, maybe the outcome of the recovery could have been positive. Instead after the initial diagnosis from our engineers from what was left of the drive, the job was deemed unrecoverable.