I need help with digital signature settings/preferences

I setup my digital signature 6 months ago. I setup it up to never ask me for password when signing documents. I have the following two problems with the setting:

1. After a short period of time(one/two weeks), it would ask me for a password when signing the a document. Even though I had specified under "Digital and Certificate Settings" to never ask me for a password.
2. After not using my signature for 2 months, it's was no longer coming up when I wanted to signed a document. I needed to set it up again from an old file.

Anyway we can prevent all this from happening again?

Thanks