Hopefully you'll never have to use it. I use what ever it takes to get me out of the situation and fix it as soon as possible. I'm not going to change two tires on the side of the rode or trail. If there's not much difference I wouldn't worry with it. A worn 33 versus a new one is usually an inch. If it bothers you you can always pick up a used tire of the same size somewhere. my 2 cents