When I install wire nuts, I twist them till the wires coming out the bottom start to twist. When I remove a wirenut that I've installed, the wires are twisted together like they were pre-twisted with pliers.
Have to be careful, though--I've had it happen a couple of times that I twisted the wire nut till the wires broke out the top!
I've also broken a screwdriver bit tightening the screws on outlets.
They say "loose wires cause fires" so I err on the side of tight.
Yes, somewhere there is actually (I think) technically a torque number. Too tight no good.
Our wiring was all done when the house was built 16 years ago. Before we closed I actually tested all the outlets with an outlet tester, get this, brand new home, I found 13 mis-wired outlets (crossed between the common) and mis-wired GFICs
I only discovered the light switch issue around 7 years back as my wife's company moved her to work at home, set her up with a nice Dell Work Station, Monitors, office phone, VPN to her company headquarters ect.
Being the system had to have ethernet instead of Wifi the problem for me was getting a connection to our router on the main floor to her second floor office. Would have been insane difficult as router was in the closet below a staircase and the wall in the room was the second floor wall right above the staircase.
Soooooo I they sent us a Netgear Basics power line adapter. It worked PERFECT, Typically RED (bad signal) Yellow (ok signal) and Green (excellent signal) Anyway, We had green but whenever we turned on the ceiling light it would turn Yellow. It was amazing, at first I thought maybe the LED bulbs were sending out frequencies and interference in the power line, nope. Took the light switch out and one wire in the wire nut slipped right out, could see lite arching, put it all back together and stayed green for years.
I was actually quite impressed with the power line adapter using them in the security business was always less than desirable and almost a sure thing there would be trouble with it down the road in time. Im also big on ferrite core snap online filters for no other reason than the are inexpensive and can filter out line noise.