I have two 25 year old Kersenbrocks with a 3/8 - 11 thread. Have used them around the world in all sorts of different climates. The brass screw goes into wood. Dave Kersenbrock said to just clean the wood threads with Vaseline about once a year and the wood should not get brittle. It hasn't so far.
I have played with cues from 10 to 60 years old and found that almost any joint that has been machined with some care will last as long as you like...unless you use it for other purposes...like golf, tennis, etc.
I like the old fashion 5/16-14. Seems to me to be the prefect number of threads and size. Not too many threads like the -18............which takes longer to screw together.