It's easy to say you should order up all 3 of my boards as a package in what I call the "Trifecta". But the truth is you only need what's not working. Now lots of people do purchase them all to keep there investment new and fresh plus have something that offers you a lifetime warranty. But the 2 most important boards are the Ultimate MPU and Solenoid Driver boards. These 2 boards are truly the heart of your game and if there working flawlessly, the rest of the game has a better chance of going for another 40 years.