How often does webroot update its threat protection?

Hello jinlisa, welcome to the Community!
 
Webroot works differently in that there is no need for bulky, slow, daily definition updates  The definitions are held in the 'cloud'.  As a result, the definitions are ALWSAYS up to date.  The moment Webroot has identified a threat, everyone globally is instantly protected against that threat without having to remember to download updates.
 
You do need to make sure that the program itself is updated, which is very easy.  Updates to WSA usually come ine automatically without the need for you to do anything.  Most of the time I do not even notice when it has updated to be honest.  
 
To make sure you are correctly set to have the WSA software itself automatically update, please check the following:
 
Open WSA
Click the Advanced Settings button at the upper right
In the default tab on the left, Install Options, the top item on the right panel should be checked to enable automatic updates.
 
That is all :)
 
I hope this helps!