I sometimes find myself doing the same thing. There are two sides to this act, one that can help you and one that can hurt you. When I play a cash game, I pick a set amount to raise, be it 3 or 4 times the bb. I will open raise that amount with any hand I want to play. This helps me disguise my hand strength, but as the session wears on, people start to make calls with weaker hands. This goes to the one that helps and one that hurts. If you continually raise the same amount with the same hand types people will start to narrow down your likely hands, based on note taking and histories. That is why I do what I do. If you do this, you need to be mindful that later in a session you can expect weaker cards to call, so you need to be good at reading actions and opponent strength. Mind you I don't raise with any pocket pair lower than TT, instead I just call and hope to set and rake a HUGE pot.