It would take a long time. Some of the cues I have that are 40, 50, 60 years old just have regular French leather tips that are old and they are as hard as a rock. Much older than that and they start to disintegrate.
Maybe not hard as a rock, but hard enough to affect playability. I've always had two shafts for my cues and play with one on even days and the other on odd days. Keeps the tips playable. Some people think that having a cue with one shaft that's never been played with a selling point. I don't.