It depends on the state that you are in and the toleration to them police officers.
Here in cali, 3 over is still fine but that's just me saying and experiencing. To not waste their time, they'll do 5 over but some chp are pushing it to 10 over because A) They hate the nagging and argument by them drivers and B) they can literally bust yall california drivers cuz I know how yall drive and they will be so busy writing up tickets for days. You think the judge liking this? It is almost like a law that prevents the cops from setting you up for failure.
I usually go 5 over on the highway but our odometer is not accurate. If 65, i'll do 70 but the speed camera will record it as 68. What them chp wants are them 80mph in a 65. If residential like 25, I'll make sure I'm 25 exactly around school zones and under 30 if not posted.
Last time I was pulled over was not too long ago. It was almost to midnight and taking the scenic route to go around the altamont pass and around the mountain on a dark dark night with nothing but the full moon. This was on the same night when there was an eclipse happening. Chp came out of nowhere from a street to my left. With a 2 lane highway, if there is nobody around, I'll just cruise for fun but if there are something behind me, I'll make sure to hurry it up a little bit because that guy might be in a hurry for work or to drop someone off at the SF airport. Well if you are taking the scenic route, you are not in no hurry is my deduction. I got pulled over and the chp said I was going 65 in a 45. I said no effing way, the highway speed if not posted is 55. He looked through my background check and let me go with a warning. I spent the night in the bay and when driving back by the next morning, I took that scenic road just to look for some speed signs. yep, I was right. Posted sign said 55 through them curvy mountain roads.
I stopped to take that picture for future references because I want to see that same cop again when I be driving that same stretch of road again. I'm no lawyer but me and my mn cousin loves to sue cops for some odd reason. I dunno why. We just do.