In my freelance work I do (for the most part), but in my own game I pretty much just tell the players "Hey, level up before the next session!" I find the CR system to be not too bad at gaging appropriate challenges, but I generally don't bother with XP.
In the adaptation of the old Dragonlance modules I worked on for Sovereign Press, we abandoned the XP system and simply had the PCs level up at the end of each chapter of the module. Because it was an adaptation of a 1st edition module, the PCs would have leveled much faster and we would have ended up with a bunch of epic level PCs by the end rather than 8th or 9th level like in the originals...