Or, devils advocate, just go ahead and treat them. The factory treatment will only last so long. Might as well go ahead and waterproof them before you end up on a trip with wet feet.
It's just like anything else, your mileage may vary.
I like the Nikwax stuff, worked well for me. I waited for my old leather Boreals too long, then they leaked...treated them and they were clearly much better.