Radiator cores do go bad, but is not a preventative replacement item. It is a good idea to replace the radiator hoses, block to firewall hoses, and water bottle hose at the same time.

If you smell coolant at the bottle, suspect hairline cracks in the cap. It is a cheap item to replace the cap, but do NOT replace it until the hoses are replaced. You do not want excess pressure to blow off a radiator hose that is weeping already.

Inspect the overflow bottle carefully, especially the bottom where the electrical connection is.

So long as the car has had quality antifreeze, and regular flushing, the heater core should be in good shape. Have you installed a cabin air filter? If not do so. And order a new filter or two when you get your other parts - save on shipping costs.
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Always willing to listen, just not able to take direction.