Not every app can be installed to the SD card, nor is it advisable due to performance losses and higher rates of card failure (meaning total data loss). Those that can be moved will still leave part of the data on the internal storage, and the amount transferred will vary from app to app. It all depends on how it was programmed and functions. Apps will always install and update to the internal storage, so every new install and update will require you to move them again.
Generally speaking, the SD card is best suited for stand alone files that aren't constantly written over. Photos, music, video, documents, etc.