FIDE rules of Chess : When does a player have to say "j'adoube" ?
When he/she wants to adjourn the game.
When he/she wants time be added to his/her clock.
When he/she wants to adjust a piece on its square without being required to move it.
When he/she wants to claim a draw by the triple-repition rule or the 50-move rule.
When he/she wants to resign.