90-Day Supply

A 90-day supply is a prescription fill that provides three months of medication at once, rather than the standard 30-day retail fill. For maintenance medications on chronic conditions, 90-day supplies are almost always the preferred option because they reduce dispensing fees, pharmacy visits, and — on many plans — the member's total cost-share.

Most modern plans allow (and encourage) 90-day supplies through two channels: mail-order pharmacies operated by the PBM, and select retail pharmacies that participate in "90-day at retail" networks. On the mail-order side, the pharmacy ships a 90-day fill directly to the member's home; on the retail side, chain pharmacies like CVS, Walgreens, Walmart, and Costco typically participate. The economics work in the member's favor: a 90-day supply usually costs the member two copays instead of three (skipping one full copay), and the total plan spend on generic maintenance drugs is often only slightly higher than a single 30-day fill because the acquisition cost of the tablets themselves is minimal — most of the cost is dispensing and labor. On brand-name and specialty drugs, the math is different because the acquisition cost dominates.

The takeaway: for any maintenance medication you'll be taking for more than a few months, switch to a 90-day supply. It's fewer trips to the pharmacy, lower total copays on most plans, and one less thing to forget to refill.