My A/C & Heater are shot..do I even need to replace the cabin filters?

I figure those are just necessary when those work..

If you don't use the air conditioner, heater, or vents, you won't use the cabin air filter. The cabin air filter takes out dust (pollen, etc.) from the air before it enters the cabin (passenger compartment) of the car.

You have a choice to use a HEPA filter to remove finer particles (if you have allergy problems).

The cabin filter keeps dust from coming in the car through the fresh air vents. You need it clean unless you never open the vents. It won't matter if you ride with the windows open. I think I know why so many things on your car don't work anymore.

Like Joe said, but if the fan is not running, you won't have much/any air entering the cabin. A few years ago, no cars had cabin filters.

Cabin air filers help keep the air clean of pollen,dust,dirt,leaves and bugs that can enter into the air ducts. If you dont use the blower motor to blow air into the cabin I guess you can get away w out replacing it till the car starst to get a mold smell

It's not related to ac/heat. Cabin filters are for dust particles and such that enter through the engine block area while driving

Not really. The filter exists primarily to protect the A/C evaporator from corrosive mud formed when pollen is trapped in normal condensation on the evaporator. Without the A/C operating there is no condensation.

My A/C & Heater are shot..do I even need to replace the cabin filters?

I figure those are just necessary when those work..