I'd say best thing to do is remove the tire and visually inspect them. If they look low replace them. There's also a brake pad measurement tool that is placed between the pad and rotor to tell give a reading looks like this

For the shoes it would be the same way remove the tire and then the drum to see how thin they are. Shoes generally last longer than front pads.

 

Also, they will start to squeal as there is a metal strip on the pads that will make contact with the rotor once they wear down enough.

 

Thank you very much for the info. Can I pick that tool up at a local car parts store?

 

Thank you. I'll be pulling the tires and drums within the next few days.

 

I know you can order them on Amazon but in not sure if most auto parts stores carry them. If they look really thin just replace them. You'll know once you look at them.