It's about the Money. It doesn't just happen to Individuals. It's a different scheme with large group policy holders. Blue Cross/Shield will deny coverage for Medication as I had happen. They want pre-authorization so the Doctor get it. Six months in the Doctor ups the dosage, hey deny wanting another pre-authorization. When the one year date comes around on the original authorization, they deny again, when he year date for the dosage increase comes around, they deny again. IMO, it's their way of pushing  cost. If you have a prescription filled for twelve months but they can hold that up for two or three months, they just saved $$ by only having to fill it nine/ten months of the year. Span that out over their millions of customers, that's big money.