I need help.

Hey,my breaks are constantly squeaking.I have redone all my back breaks(disk,break pads and calipers)and my front only disk and break pads.Ive brought it to a mechanic and he says everything is good with both my front and back breaks.If anyone has any idea what the problem could be please don't be shy!

certain material in brakes will squeak no matter how new or good shape they are in.

Performance pads with higher metal content will squeak, its a trade off between stopping distances and less noise, smoother stops and further stopping distance with organic or lower content metallic pads.