Out of curiosity, does anyone know what's legally required to cancel a typical subscription or membership?

For example, are companies like the NYT permitted to force you to go through a red-tape gauntlet of their design?

Or, e.g., does the law ensure that once you tell one of their agents that you're canceling, they're legally barred from attempting to charge you for the service?

It seems to me that the burden of red-tape / bureaucracy navigation is an under-discussed battlefield for consumer rights, at least in the U.S.