Rule of thumb for air tools requiring lubrication is one drop per minute.
Personally I do not like those lubricators as they contaminate your air lines and require periodic maintenance. A couple of drops every time you use the tool works fine 99% of the time, inline lubricators are more for continous use like on an assembly line.
My advice, keep the drier/filter and regulator and don't use the lubricator. Most people end up taking them off anyway.