As Beeline says, the wear pins are set to provide sufficient lining material remaining to absorb a high energy stop such as RTO. Or on carbon brakes, sufficient disk thickness. Letting them go down below-flush or bending/moving the bracket may make the brakes last longer but hazards the aircraft's stopping performance and invalidates its C of A.
Conversely pulling the brakes early, before the pins are flush, can be a very expensive business with heatpacks costing tens of thousands of dollars. The only time you would want to do this is if the aircraft is scheduled to be operating down line for some time with no possibility to routinely change brakes as they reach WTL.
Unless your AMM states hot or cold it's normal to check them cold, if only because they get bloody hot! Parking brake pressure is normal and if you can see different length wear pins that indicates asymmetric brake wear, which is not good - pull these when the shorter wear pin reaches flush.
If you have an over-worn brake and can't change it straight away refer to your MEL procedure and lock it out (if permitted). Over-worn brakes can and do fail spectacularly and you're better off with a known locked-out brake than one about to fail.