Is your bin inside or outside?

You might want a drainage hole in the bottom since the top layers may be dry while the worms in the bottom are drowning.

My bin has a screen cover over the top and I lay cardboard directly on top of the bedding. There are drainage holes in the bottom of my bin which is painted wood. My bin is outdoors in shade.

If you are having trouble with the bin being too wet, I'd switch to a layer of cardboard directly over the bedding and keep the plastic lid either off or mostly off. it is not necessary to wet the cardboard if you are finding the conditions too moist already. If you find during another season that things are drying out too much, then go back to the plastic lid.

Too much feeding and too much water are common problems for new worm farmers. Remember that even if the top layer of bedding drys out, there is probably still plenty of moisture lower in the bin. Occasionally stick your hand in to check and fluff the lower layers, shredded paper often compacts.
Most food contains a far bit of water so depending on your climate, adding water might not be necessary, some people find they need to add dry bedding to keep things right.

My bin is outside in the shade. I have drainage holes, but nothing ever comes out (the holes are pretty big too, I'm thinking that if anything does come out, it evaporates by the time I check the tray).

So basically I should use cardboard if the bin is too wet and the plastic lid for when the bin is dry?

Two last things, if I use cardboard as a lid, does it need any holes? Also, if I use the plastic lid as a cover, does it matter whether or not I snap the lid shut?

Thanks for the advice.

Cardboard doesn't really need any holes so long as it isn't coated with plastic, it will breath. It doesn't even really need to be a lid, just more of a cover/blanket over the bedding.

The lid only needs to snap shut if you expect it to blow away otherwise or if you have pets or critters who might try and get into your bin.

My bin has a screen lid to help keep critters out and I lay paper or cardboard over the bedding to keep it moist yet allow it to breath. I have a catchment under the bin but it only seems to have anything in it if the bin has been over watered, which is as it should be.

alright, thanks a lot.