The same volume level should be present no matter what source is selected. This means if you have the sound set for comfortable DVD listening, it will blast the walls down if you switch to another source. If you are not careful this can damage your speakers and the feelings of neighbors. I have personally found this to be a problem with the CD mode of mant receiver. More controls is often not the same as better.
Many people get so into setting controls that they lose the enjoyment of the movie.
Set it and forget it is usually best. Still, there a need for balance here. For example, older movies recorded in mono often need a bit more bass added. Many newer amplifiers come with several pre-set settings to emulate various listening environments such as a concert hall, a theater, a small club etc. This is a very nice feature especially if you plan to also use the amplifier for playback of CD music.