Vacuuming gravel necessary? Remove water from top good enough?

Is vacuuming gravel necessary to do a proper water change or can I simply remove water from the top of the tank and replace it?

 

jmadden93

this is a freshwater tank I assume

My target when doing a water change is to make the water I remove from my tank as dirty as possible so in FW that would include vacuuming the gravel , the dirtier the water I created the happier I was when I then replaced it with clear new water

Steve

 

I try to pick-up anything loose in my gravel but if i don't see any dirt or poop its fine to just do a water change because after all the reason your changing the water is to remove the things that are already dissolved in the water.