I have been labeled a clencher by fellow pipe smokers ... so I guess I am, although I have some rules. If it's off balance, heavy or bulky, I don't clench. I guess it's more of a feel thing and a tendency to protect my teeth, rather than preserve the stem of that pipe. I do have a number of pipes that do fit my rules though, and I clench without thinking of it when I work at my desk, shoot I have been clenching my pipe since I started typing this, and this Peterson that I smoke right now is not quite light ... so I guess it is more of a habit, than something I do consciously. I do like to feel the warmth of a good solid bowl though, when I watch TV for instance, and I have pipes for that purpose. Try what works for you man, rubber bit, no rubber bit, heavy, curved, straight, light, and so on ...