I've wrenched on all kinds of stuff from bikes to cars to boats and snowmobiles and motorcycles to go karts and lawn mowers to paper converting equipment and GE gas turbine engine. My dad taught Diesel Mechanics at a tech school so every summer brought a new project. I think torque wrenches are valuable tools when you are first getting aquainted with being a mechanic but grow less necessary over time as you get the feel for fasteners. That said I wouldn't assemble an engine without one. One thing some people overlook is the importance of using good quality fasteners that are in good condition and knowing when you can re-use a fastener and when you should throw them away. A bunged up thread can seize a nut on a bolt and give you the torque spec you're looking for without actually doing the clamping work you need the fastener to do.

My favorite bit of advice to give new mechanics is "tighten the bolt until you feel it getting loose again then back off a quarter turn". Of course this is nonsense if you feel it getting loose then you've stripped the threads