Over the past week I've started saving scraps at work to bring home to the compost. Some days this is almost entirely eggshells and coffee grounds in filters.
Is there such a thing as too many eggshells in the compost? I always used to feed my eggshells back to the chickens so I've not really had much experience with composting them.
Also, are the coffee filters going to take longer to break down than everything else?

Yes, the filters will take longer to break down; you could wait till the grounds have dried and shake them off.

The eggshells can also be broken up by hand or ground up in your blender and spread directly on the plants. They love it.

I don't know if you can over do it with eggshells, sorry. The coffee filters do take longer to break down, especially in cold weather. There are certain plants, especially azaleas, that love coffee grounds. Hope this helps.