I got PCE for the December event, and I didn't buy a bag until the end of August. But I bought 2 bags and a wallet at one store between August and November, and I stopped in often enough for them to get to know me pretty well. One of the SA's made me mad at that store by being snooty, however, so I switched my business to a store that is closer to my home (the other is closer to my job, which is good because I'm leaving that job in 2 weeks).
I just bought a bag with my PCE (gave it to me even though I didn't have my card physically with me) at the new store and the girls there are so nice. I ordered the slim leather Carly and the girl that ordered it for me made me pretty much promise to open it there in the store when it comes in!

They are knowledgable and give great service. Besides the fact that this store is great, I am going to make sure I always shop at this store so I get PCE again.
I think whether or not you get PCE not only depends on your purchases at one particular boutique, but also if you have a good relationship with the store in general. Do they know you, recognize you, etc. Also, make sure in your account that it states that you want to receive mail, because I heard that can prevent you from getting one as well.
HTH!
