We are out of state, we go to Vegas once every 2 or 3 months and always stay at Stations. We play mostly quarter BP, mostly 8/5 bonus. I also play blackjack & three and five play 8/5 quarter BP, and slots (but very little of slots). We both play on one card (I do think that has made a difference). We receive the postcards every month, nothing that great but it's usually 2 free nights during the week at Red Rock/GVR and 29 on the weekends, or 3 free nights at the other properties. Plus $35 free play, a couple buffets and 3x points. We haven't noticed any reduction in the frequency of the mailings.
Can I ask what you are playing or how often you go?