I also have Medicare supplement (AARP/UHC) which pays for my gym membership. However, I am not sure that I can join more than one gym at a time.? Sounds like it might be too costly for insurance company.
When I was getting my Medicare supplement last year, choosing a high-deductible Plan G made sense for me financially, but I couldn't get one that also has gym benefits, so I was having to choose between the two. So I questioned AARP/UHC thoroughly about how Renew Active works.
I assumed that instead of my paying a gym $10 for a day pass, I'd give they gym my Renew Active number and that would pay for the day pass. But that's not how it works. At each gym, I have to go through the process of signing up for a membership, but neither I nor Renew Active pays for the membership. Instead, Renew Active pays the gym every time I scan my key tag. So the gym signs me up as a member but gets paid like I bought a day pass.
Because I travel fulltime, I specifically asked Renew Active (or, actually, an AARP/UHC supervisor--there doesn't appear to be a separate Renew Active set of people) if they really wanted me to be a member of dozens of gyms instead of getting day passes, and she said yes.
I'm a member of six different YMCAs, in Illinois, Florida, Alabama, and Tennessee. Each YMCA membership works at any branch in their geographic area, but the Tampa YMCA membership doesn't work in Orlando, for example.
As for being in one area, which is how most people live, in Tampa I had memberships at three locations at the same intersection--a hospital fitness center, Club Pilates, and Crunch. I also had memberships at Esporta (LA Fitness), the Tampa YMCA, and StretchLab, and used all of these on a regular basis while I was in Tampa.
Most of the "national" memberships work anywhere, like LA Fitness and Crunch and Anytime Fitness. Planet Fitness is an outlier--I stopped in to sign up at one just to have it available, and was told my Renew Active code got me the membership that works only at that particular location. She offered the upgrade that
athena53 mentioned--$10 out of my pocket to have access to any PF anywhere--but I declined. She also said that not all PF locations participate in Renew Active at all (e.g. the one in the next town over doesn't).
If you read reviews of gyms, the majority of the bad ones are complaining about the financial side (cancelling a contract, stopping automatic withdrawals), so having a membership with a gym that doesn't allow them access to your credit card or bank account would be a big benefit.