How much do marker renderings factor in?

Well I was thinkin to go college to do an extra year purely for building more of a portfolio and for more experience around the sort of materials you may use in a studio. Because while doing my graphics theres not been much materials available to us. Yes you get the wood and the foam and metal but nothing like clay and good 3D computer software. well would it help or is it no different than what im doing at 6th form? cheers, and sorry 91286 im not sure how much marker renders factor in. I have heard that its more the sketching then anything.

anyways please help.
cheers