Heh, I feel pretty awful about this, but I realize that in future games I'm going to spread out adventures a bit more, chronologically, and give incentives to take time off.
In game, the campaign started on October 20th, and now it is late February of the next year. About 130 days. They've gone from 5th to 12th level. That's sort of like the U.S. Military going from sabers and cavalry charges to tactical nukes and stealth bombers, in 130 days. Four months ago, there were only a few people in the world 15th level or higher, and they were very famous. Now, in order to keep the party challenged, I'm finding myself inventing a lot more powerful people than I originally imagined.
I guess they all just leveled up really fast too. Then again, there has been a world-wide scramble to grab up positions in the power vacuum left by a coup, but still, I'd rather that much advancement had taken 5 or 10 years. Problem is, the group is used to advancing a level every 3 or 4 sessions, and I'm nearing the climax of the campaign, so it wouldn't make sense to have events slow down, would it? I guess they'll probably end at around 15th level, at which point I probably won't have had enough time to adapt to their new powers.
Oh well. It will still be fun.