+1 on square-tapers being good with proper installation.

I was amazed the first time I used a torque wrench to tighten down crank bolts according to factory specifications. 40Nm is waaay tighter than I would ever dream of torquing down anything by hand. Promptly reinstalled the cranks on all my bikes the same way - some were loose enough to definitely get a failure down the line.

I would advice against just tightening crank bolts repeatedly - a full reinstallation is needed to get the proper torque. Oh and beewax or Locktite on the threads helps