My rear breaks were squeaking and my normal mechanic said that my discs were old so we replaced my pads and discs. I had been averaging about 25.5 MPG, unless I did a lot of city driving. The old pads still had a lot of thickness and the discs were a bit rusty but we replaced them anyway. I filled up after the break job then did a lot of highway driving. I filled up again and did my usual MPG calculation: 28.1! Wow! Apparently old brakes need to be greased and maintained even if you don't replace them that often.

FYI.

Chris

 

so they are squeaking when you applied the brakes;
seems more like you just adjusted your driving habits
(or something) and the brakes were not instrumental

 

I use a temperature gun to make sure the left and right rotors are the same temp after a drive. If one is hotter or both are really hot, it could mean they are dragging. Unused brakes can bind up with dirt and rust so they don't release properly when your foot comes off the brake pedal.