Medicare Supplement Plans cover the Gaps left by original medicare coverage. The following diagram depicts the medicare options and the color coded table corresponds to the "gaps" each lettered supplement plan covers. For example, the F plan covers all the gaps while the A plan only covers the Part B coinsurance. Not all plans are offered by all insurance companies and some even offer fitness plans augmenting their other coverages. Premiums typically increase every year. As long as you pay your premiums, you are guaranteed coverage. Outside of either your initial or a special enrollment period , you would need to health qualify for new coverage.
Medicare supplement insurance plans have been around as long as Medicare and each plan specifies which "gaps" they are covering as well as what your liability for each is. Medicare supplements are offered by insurance companies, not Medicare. The coverage under each type of plan is standardized through Medicare but the pricing and any added services are up to each independent carrier. Additionally, which supplements to offer and underwriting eligibility are under the purview of each company as well. The colored font on the supplement table corresponds to the same color depicted on the diagram above.
The F plan is the "peace of mind" plan. While this may charge the highest premium, clients are assured that as long as they pay the premium, they have 100% coverage for medical coverage and up to and including 100 days in the hospital. Now, that is peace of mind. It is rumored that this plan will no longer be offered after 2020 though those enrolled, as long as they continue to pay premiums can retain their plan.
The G plan was reintroduced in 2015 as a good alternative between the F and N plans. Like both the F and N, the G plan covers 100% of the hospital gap services up to and including 100 days. It is priced competitively with the N plan but only charges the annual deductible, therefore no co pays. Typically this is my plan of choice, as all your costs are known.
The N plan is the "value" plan. Introduced in 2010, this plan is marketed to clients who wanted to exchange their higher premium for one which charged co pays for some services and an annual deductible. The plan does cover 100% hospital services up to and including 100 days. I believe the G plan is currently a better value, since it does not charge any co pays.
In addition to a Medicare Supplement policy, you must enroll in a prescription drug plan to avoid paying a penalty.