Find out the area your in. If there are only black bears and cougars, your rifle is all you need (assuming you're not hunting with a bow).

If you are in an area with Griz and Wolves, might not be a bad idea. Find out from others in the area what they recommend. Here in Washington I've never worried about it (only blacks and cats) but my Idaho hunt this fall I'm thinking about it (Griz and dogs).