Do I need to replace the brake calipers when installing new brake pads?

caliper pistons either push in or screw in and you have to push or screw the piston in to get the new pads on because the new pads are thicker than your old pads,there's no way to install the new pads unless the piston is all the way in! I've replaced a bunch of pads and NEVER replaced a caliper when replacing pads unless one failed,only clean it up,grease the slide pins,etc. the only reason one would replace a caliper is if were sticking and wouldn't release/slide/or very badly rusted. who told you that,Firestone Complete AutoCare?