Viking, don`t you know a chessclock? A chessclock has one part for every player and runs only if the player has to move.And if the player has moved he pushs a button and only the clock of his opponent runs. So it is clear that you can certainly use the opponents time! For instance in 10moves / 30 days both player has to reach the 10th move until the 30th day is over but every player has the 30 days = 60 days (without weekends).And if you move 3-4 moves a little bit faster you have more time for the rest of the ten moves.Btw this is the regular mode which is used by chessplayers all over the world.In our OTB-Games (this morning I have lost:( ) we play 40 moves / 2 hours and then 1 hour for the rest of the game.That means that the game can run four hours until the first timecontrol (40th move) and after six hours it is over at the latest (today it was earlier) .In fast games we play an half hour in blitzgames 5 minutes (every) for the complete game.