ok so i noticed a few days ago on my way to work in the morning that when i sit at idle my headlights dim down a little, and when i rev up the engine the lights come back up to normal. is this normal or does my charging system need to be serviced?

 

It's normal on these old motor components. I don't think your alternator is bad unless you've been having issues with it causing your car to die on you at a stop.
You may want to change out your battery if it's old. Another consideration is the voltage draw. If you have a system, there's your problem. That's a huge voltage draw, one that our little 75 - 90 amp (at the highest) alternator can barely handle.

 

Check grounds. If you want to make that a little better, get a grounding kit.