A small note that survives a long break
On a series page, choose the season and episode you last finished. Press Save checkpoint and read the confirmation beneath the form. That is useful when a gap of several weeks makes every episode thumbnail look familiar.
Finished is different from started
The checkpoint means completed, not currently playing. If you stop midway through an episode, save the previous completed episode and use the viewing service's own resume control for the exact minute. Series9 does not observe another site's player or automatically mark episodes watched.
Several versions, several notes
The Office UK and US do not share a checkpoint. Neither do the different Doctor Who production entries. Choose the right starting year before saving. You can keep a note for more than one version if you are comparing them.
Finding your note again
Open My List and look below the saved posters. Checkpoints remain useful even if you did not save the poster with a heart. Clear checkpoint removes only that episode note. Before moving to another browser, include those notes in a backup.