There’s a torque spec on every single bolt in every single vehicle made in the past 50+ years.
I agree about the torque . . . I usually don’t torque bolts unless it’s something critical
For example . . .
Cylinder head bolts
intake bolts
I have never had a spark plug loosen out or blow out because I didn’t torque it
I’ll now say something which may infuriate some, but I stand behind it
I think it’s far more likely that somebody crossthreads the spark plug threads in the cylinder head, versus a plug loosening because he didn’t use the torque wrench
And I absolutely do not believe those Ford plugs blow out because somebody didn’t use a torque wrench
Torqing techniques for the "too-cheap-to-buy-the-correct tool: I’ve used
Take the bathroom scales out to the driveway, press on it for a certain number of pounds, then press on the wrench w/ the same force. You have to first figure what the force is with the appropriate length factor for the wrench.
Use your weight, presumably known, and stand on the wrench at the correct distance from the nut. Works well for axel nuts.
Something else I tend to do for torque is once the bolt or nut begins to feel “snug”, I then give it another 1/4 turn. I wouldn’t do this on head bolts or something like that but it seems to work on just about everything else, at least for me. Your mileage may vary but this is personally how I tighten lug nuts as well as spark plugs.
I did some tests on some bolts and such I was throwing away. After 1/4 turn past snug, you tend to feel like you are hitting a wall. Keep turning much past this point and you are going to shear off the bolt or strip something out. You kinda get the feel for what is tight after a while. Exceptions to this include axle nuts as well as the nut attaching driveshaft yokes to a spline on a differential. You feel like no amount of force is too much based on the required specs.