Saved lessons persist across page refresh and filter reset. They should not persist across page visits, and could (conditionally) persist across filter resets.
If saved lessons are to persist across filter resets, there needs to be an indication that lessons are being saved by the page. This could be done in a few ways:
'email to me' button could appear only when lessons are saved, and persist at the top of the page as long as there are saved lessons.
there could be a separate 'reset saved lessons' button as well.
Saved lessons persist across page refresh and filter reset. They should not persist across page visits, and could (conditionally) persist across filter resets.
If saved lessons are to persist across filter resets, there needs to be an indication that lessons are being saved by the page. This could be done in a few ways: