If you tell Thunderbird to remember your sending and receiving
passwords, and not use a master Thunderbird password, you will
never be bothered by a mail-related password again.

I don't feel safe about Thunderbird storing passwords and not protecting
them, so that anybody that gains access to the disk can read all the
stored passwords. Even if you live alone and there is a key to the
house. You do not know if one day in the next five years you will have a
visitor, a guest, a partner, a worker, a thief, a nurse... or a clever dog.