That can make a difference in some recipes. It is not an easy task to cut them evenly. The best way is to use a large serrated knife. Cut into the layer partially, then rotate the cake while gently sawing with the knife until you have made a cut through the entire perimeter. Then it is much easier to hold the cake in place and cut through the center to the other side.
Some people suggest using dental floss.
I guess that would depend on the texture of the cake. Well, after doing some research, I decided it was time to get one. Look for a good deal in stores and catalogs. The point is that they can be used just for dough making. There is so much less mess than with a mixer, processor or by hand.