102k miles and my whole drum brake assembly is factory... Just change shoes or whole drum?

Car is a 2004 Honda Civic VP coupe that I bought new. Honestly I've never even touched the rear brakes and it hasn't been a problem until recently. I get a lot of vibration in the wheel while braking and while my front rotors are in pretty rough shape, I'm pretty sure it's the drums giving my grief despite not making any noise. (I got new rotors anyway just in case).

So should I swap out the whole drum or just the shoes? And how often do you guys need to replace all the springs and whatnot? For the record this car has been in the salt belt most of its life (Michigan/Illinois).