gnupg cache

In order to have gnupg cache your passwords from gpg-agent, you must set

~/.gnupg/gpg.conf

use-agent

and in

~/.gnupg/gpg-agent.conf

default-cache-ttl 3600 (min)
max-cache-ttl 3600 (min)

which is the time the password will be kept in the cache, and the maximum time it can be kept.