Well, the new ACKS campaign seems to be off to a strong start. Two sessions down, and I think the PCs have a chance to hit level 2 upon completion of the third session.
Assuming they level every third session (we skip one Saturday a month) and assuming the campaign remains vibrant, we could be looking at a game that covers all levels of play in about 12 months.
I have no idea if the leveling will stay at the same rate. As it is, I'n addition to the usual expo for overcoming adversaries and treasure looted, I'm also awarding expo for completing adventures, minor expo for successful proficiency use and a 10% bonus for completing weekly adventure logs at the Obsidian Portal site. All that, and the third session should allow them to hit level 2. It isn't guaranteed.
A level a month of mostly weekly gaming sounds about right to me, I just hope it fits with my players' expectations too.
When it comes to OSR style gaming, what is the rate of advancement in your campaigns?
(I'm avoiding 3x and 4e, as they are their own beasts, especially with the rate of advancement)