Why annual review matters
Part D plans publish new formularies and premiums every year. The plan that ranked #1 for your drugs last year may rank #15 this year. Drug tier changes, formulary removals, network exclusions, and premium increases compound annually.
MA plans similarly change networks, drug formularies, and benefits every year. A plan that was great in 2025 may have lost your specialist or moved your medication to a higher tier in 2026.
Original Medicare itself doesn't change much — Part B premium adjusts annually, deductibles tweak. But Medigap premiums increase based on the rate method (attained-age plans go up faster).
Net effect: people who don't re-shop annually pay an average of $400-1,000/year more than they should. Compounded over 20-year retirements, that's $10,000-25,000 in waste.
The October calendar
September: Annual Notice of Change (ANOC) arrives from your current plan. This document lists every change for next year — new premium, formulary changes, network changes. READ IT.
October 1: Plan Finder updates with new-year plan data. You can see all 30+ Part D plans + all MA plans for your zip with new pricing.
October 15: AEP opens. You can submit enrollment changes for January 1 effective.
December 7: AEP closes. Last day to make AEP-eligible changes.
January 1: New plan is in effect.
January 1 – March 31: MA-OEP (only if in MA). Buffer period to switch MA plans if needed.
The 30-minute review process
Step 1 (5 min): Pull your current medication list with exact dosages and frequencies. Update for any new drugs from the past year.
Step 2 (5 min): Read your ANOC. Note: did your premium change? Were any drugs moved to higher tiers? Did the deductible change?
Step 3 (10 min): Run your drug list through Compare My Medicare or Medicare's Plan Finder. Get the ranked list of plans for your zip.
Step 4 (5 min): Compare top 3 alternatives against current plan. Verify: drugs covered? Premium? Deductible? Total expected cost?
Step 5 (5 min): If a different plan saves $100+/year for the same coverage quality, enroll in the new plan. Old plan auto-disenrolls when new one starts.
MA plan annual review
If you're on an MA plan, your review checklist adds:
Provider directory verification: are your doctors still in-network for next year? Networks change — losing a specialist mid-year is a big deal.
Drug formulary check: same as Part D review.
Prior authorization changes: did the plan add PA requirements for services you use?
Star rating check: plans rated below 3 stars for 3+ years can be terminated. If your plan dropped, your enrollment may be at risk.
Benefits comparison: did dental, vision, hearing benefits change? Are extras still useful?
Medigap annual review
Medigap reviews are simpler. Your Medigap doesn't change benefits (federally standardized) but premiums increase annually with attained-age plans.
Each year: check if a different carrier is cheaper for Plan G in your state. If yes, you can apply with new carrier — but you'll go through medical underwriting (outside the 6-month OEP). Only switch if you're healthy enough to qualify.
Some states (Birthday Rule states like CA, OR, MO) let you switch Medigap carriers annually around your birthday with guaranteed-issue. Check your state.
After AEP — confirmations
After enrolling in a new plan: confirm the enrollment within 2 weeks. New plan should send a confirmation letter or call.
If you don't get a confirmation: call the new plan directly. Don't assume enrollment processed.
January 1: new plan ID card should arrive. If it doesn't by mid-January, escalate.
First fill in January: confirm the pharmacy uses the new plan, not the old one. Sometimes pharmacies have stale info — bring the new card.