During my work life, we said that "Knowledge is power". And Medicare insurance plans are an example!!!
Reading up on things is how to stay informed.
In your situation I would recommend that you be careful how you change plans each year. And do not sign up for a Medicare Advantage plan. Here is why:
1) With original Medicare (Parts A and B) you can self-refer to any doctor in the US who takes Medicare. THAT IS KEY. Your Medigap plan should do the same! So, you never have to worry about your doctor not being in the plan.
The different Medigap plans vary in benefits and premium prices. To be able to compare them Medicare assigns a letter to each plan based on benefits it offers. Below is a link to a table on medicare.gov which compares each letter type of Original Medicare Medigap plan. When you choose between plans, they should have the same letter to compare "apples to apples".
2) Medicare Advantage plans MAKE you go to their network of doctors (they pay them less), and they easily may lack the expertise you need. And you need approval for tests and procedures. Many places are dropping them. Mayo Clinic does not take Advantage. Mayo Oncology warns people to check with their insurance to see if their cancer treatment is covered! Mayo brochure also states that people with Original Medicare (Parts A, B) do not need to check!
3) When one originally signs up for Original Medicare, all Medigap plans have to take you no matter your health. But after, they are not obligated to take you, and pricing may be higher. So, someone signing up for Advantage, and then later wanting to go back to Original Medicare, may find difficulty in finding a Medigap plan.
If you are only switching between Medigap plans and always keeping Original Medicare, I do not know if there would be a difficulty for you and if price is higher than if you had stayed with just one Medigap plan.
https://www.medicare.gov/health-drug-plans/medigap/basics/compare-plan-benefits