There are a number of websites offering CME online. A Systematic Review of the Effect of Continuing Medical Education Strategies. In other words, the best way to use CME would be to have quick access to it after you've identified a need for it, rather than using it when you have time and hoping you remember it all. This is probably not isolated to medicine but, rather, is a more general failure of educational style - to try to memorize things by rote rather than learning how to find what you need when you need it. This is the self-directed learning aspect of EBM, and fits very well with the idea of finding things as you need them in the medical literature, on the Internet and elsewhere.
Nobody can remember everything, particularly in a field that changes as quickly as medicine does.
Someone still has to pay for these, whether it's the library affiliated with your medical center or your own personal subscription.