I have just recently purchased 1Password, and have the following observation.
The tool is designed as if you had never created a login on the web before. If this is not the case, it is extremely cumbersome to:
A problem that frequently occurs is that changing a site password is often done on a profile page. When you save the updated password, the 1Password plugin saves all the fields on the page (mailing address, email, phone no, etc).
Consequently, to avoid this, I have to:
3. Generate a new, more secure password
4. Change the password on the site
5. Do NOT save the updated password via the plugin
6. Open the 1Password application and change the password there sans the extra fields.
It would be nice to have a prompt when you change a password on a web page that lets you select which fields get saved.