I’m with Tim, even though I know and have split off juggles with a hewer who lams up his own handles and know them to have served him well…
I’ve had equally long service with solid handles and natural curves. And my style of lefthanded hewing, log to my left, left hand forward, requires an especially heavy and immediate curve. My power / lifting / control hand is my forward hand, my forward hand, is to the log, not the fingers of my opposite hand, so my southpaw requires a couple inches of clearance, just south of the poll.
Service life on any handle, but especially ax handles hinges on how well they are hung more than any other factor. An extra fifteen at the shaving horse fitting it just so, has proved to be what adds years to a handles service for me.
But then, I’ve never found the logic in sawing or laminating curves into wood, it grows crooked everyday !
"We build too many walls and not enough bridges" - Isaac Newton