Playing against the same players.
when you play daily or monthly basis against the same players , you have an idea of how to play each before sitting down at the table. That is something positive, but keep in mind that they also know you.
If you are an observer and intelligent player , you should know your common opponents and exploit their weaknesses , giving you an advantage when playing against them .
Against opponents who are not observers and play based on his letters only you should not change your game as they continue making the same mistakes all the time. Against a rival observer adjusting his game based rivals , you should vary your game to make it hesitate.