didn't answer the question AT ALL

the pins are a replaceable item as are the boots

pull the slider pins and inspect them - and replace them if necessary

if they can be cleaned and regreased along with boots do so

next check the anti rattle plates  and again replace if necessary

one long shot is the piston does not retract as much as it should - there is a procedure to test that but likely only if a high mileage vehicle

also when doing brakes not a bad idea to replace rotors at the same time

bleed
system thoroughly