My big secret .... if I don't know the area, I at most go 5 mph over.
Otherwise, if I know they give tickets at X mph, I typically go 3-5 mph less than that.
In Connecticut, that means that 10 mph over the limit on the highway is OK. In New York State, once you get several hours out of the NYC area (like past Albany in any direction) you are wise to not exceed 72 in a 65.
And I didn't have t buy a radar detector.
Or my favorite trick. Find an idiot driving like a moron and stay 1/4 mile behind them. So far, I had this work once. The idiot got pulled over and I slowed back down to my normal pace.
And the sad truth, if you are doing 80 instead of 70 for a 30 mile drive you are saving All of 3.2 minutes. At 80, it will take 22.5 minutes. At 70, it will take 25.7 minutes. At the same time, you can get a speeding ticket and you are wasting money on lesser fuel economy. So, what is it that is so critical that you save that 3.2 minutes most of the time?
There was one time I was speeding and didn't care. my dog flipped himself over a baby gate when it was a puppy and landed on it's head. For a few hours, he was wimpering (among other things) every time he had to move. Something was wrong with his neck or skull and it was midnight so I had to do something like a 60 mile drive to an all night emergency room for pets. I was doing about 85 mph. And if I got pulled over I'd tell him what happened and I fear that my dog is going to die (which was the honest truth). So, that was one time where I felt saving 10 minutes might actually matter.