Setting gc.refLogExpire

How do I set gc.reflogExpire so that items will never expire?
What other time interval formats does it accept?

The man page says that you can set it to "90 days or 3 months," but doesn't specify what format it expects.

From stackoverflow Readonly

• I’m not sure where the format is documented, if at all, but git reflog uses the approxidate function from date.c to parse the expiry time. One of the possible values is “never.”

  From Aristotle Pagaltzis

• Setting gc.refLogExpire to "never" should do the trick.

  From Charles Bailey