Well, I didn't always own a torque wrench. I rushed to buy one after I broke a seat post clamp. I thanked my lucky stars that the bike seat post clamp/seat tube interface on my carbon bike was thoughtfully designed, in that the cheaper seat post clamp broke, instead of cracking my seat tube.

So for me, it was the smart thing to do. Especially since I am slouching towards independence from the bike shops regarding maintenance.

When people who are owning carbon frames for the first time ask me for advice, I always say get a torque wrench and a Deda Dog Fang (or something similar).

Good luck.