Ultimately, there are too many potential milestones if you use all the suggestions given in the book. With my milestones above, the PCs could be 14th level when they face Strahd if they do everything. I designed it this way because I want maximum possible level the PCs can be when they face Strahd to be level 15. I don’t think the encounter would be challenging enough if the PCs were higher than 15th level.

I also want to allow for the possibility of another milestone based on something the PCs pursue or some event that unfolds that isn’t part of the “script” of the written adventure. So having the PCs max out at level 14 is perfect. If they engage with the campaign enough to find or create a new milestone, they can be level 15 when they face Strahd for the final showdown. Of course, if they don’t complete everything in the campaign, they could be much lower than 14th level; they could even be the level 10 claimed by the adventure itself. Wizards seems to think a level 10 party has a chance against Strahd, so I’m ok with that too.

I didn’t make restoring the Wizards of Wines winery a milestone in my campaign for a couple reasons. First, the PCs found the Sunsword in the winery, and I didn’t want them to gain two levels at once. Also, restoring the winery to full capacity involves defeating the druids on Yester Hill and defeating Baba Lysaga, both of which are milestones of their own. Also, technically, the PCs would need to recover the third missing gem, the location of which is not given by the adventure. So if they pursue that, I would need to come up with its location, and that could easily be another milestone.

I also tried to set up milestones so there was a milestone associated with each of the major chapters of the adventure (some chapters don’t have much going on, so don’t warrant a milestone).

I see my list of milestones as a guide for the campaign. It allows me to chart the progression of the PCs and make sure it’s in line with what the campaign is designed for. In the heat of play, I try to keep the progression well-paced. So a given milestone/level gain may be delayed a session or come a session early, just to try to keep the progression pace steady. I aim for an average of two to three sessions per level. I want to avoid PCs gaining a level two sessions in a row, and I want to avoid PCs going more than three sessions without gaining a level.

At the end of the day, though, I want the milestones and the level gains to make sense. The PCs should level when they accomplish something important. So I try to balance that with the pace of progression. It’s usually possible to do so. If nothing else, you can always speed up or slow down a session so it ends up where you need it to.