Thunderbird e-mail client: How long does it take to train the spam filter?

Factual Questions
1

As a Mac user, I’ve been using PowerMail as my e-mail client for more than 15 years. But, it seems that PowerMail hasn’t been updated in a very long time now, and it freezes up and chokes on certain incoming mail now that I’ve upgraded to Yosemite.

So I’ve switched to Thunderbird, and I have one question:

How long do I have to keep training T-bird’s spam filter before it starts automatically sending spam to the Junk folder?

At the moment, T-bird is successfully identifying incoming spam, but it leaves it all in my inbox, so that I have to manually delete it.

2

In your email account settings under “Junk Settings”, make sure that “Move new junk messages to:” is checked under “Destination and Retention.” If you have multiple email accounts, do this for each one. Hope this helps.

3

That did the trick. Thanks!