How often do you need to tighen your hitch ball?

I have only had one come loose ever in 25 years of driving, I will bet dollars to doughnuts that I didn't tighten it other then finger tight and forgot to go back and tighten it. That said I carry the tools in the truck to tighten it just in case.

Now that little flapper lock thinggy I forgot to close that ONE time SEVERAL years ago, (fortunately the trailer stayed on the hitch) I will still every time get out and check at the end of the driveway before pulling out onto the road.