Great question! I have always been an advocate for retention strategies in place with M&A. If you want key people to stay, you will need to show them! I have experienced the other side with no retention and we were up a creek without a paddle of technical expertise for their proprietary systems. The challenges we found were timing and transition. How long do you retain for and how would you transition the employees after a certain period of time. The exit transition is just as important as the limited duration retention offer.