In my mom's case(s) it is worth it, she is in and out of the hospitals,several kinds of docs, and use/rentals of various things from med supply places.

We laughed when we starting getting that AARP stuff in the mail, we are getting "old", they time it around your 50th birthday, when they start with the mailers.
WE presently have full coverage type ins. through hubby's job, he won't be retiring for another 15yrs.
But Medicare combined with AARP has helped my mom, plus she lives in NJ, on fixed income (S.S.) for those in that situation, the state combined with the US Gov. have a drug plan, she only pays a co-pay of 5 dollars per refill, naturally they are always generics unless they're only non generic still.
I think AARP has been good for her and they are always pleasant to talk with when one needs info.