The real problem with not using a torque wrench is of over torquing the nut/bolt on lower torque value nuts/bolts which put undue stress on said item or item being bolted on. The same could be said for under torquing items like head bolts. Sometimes it really matters, sometimes it does not.
Now how often to people put their street car on the rack and do a nut / bolt check? When we run the formula cars, we do a nut/bolt of each corner after each session and then back in the shop after a race weekend. For my duster, I do at least once a year, as I don’t drive it much. For a daily street car, I’d torque it as when do ya ever do a nut/bolt or check of it after said install? Yep never…
