The first time I opened the box and read the rules, we started playing with nothing agreed upon before the game. We scored 16 (of 25). I felt pretty good about it. Immediately after, we agreed on discarding oldest, and 2-3 other things.
I think you can play without agreed upon conventions, but not for more than a game or two. If every time you clue a card, you have no idea whether your partner is going to save it, play it, discard it, save every card right of it, discard another card, or play the card left of it...that's too random. It will be to frustrating if they do something different every time in the same situation. How could you play 10 games without starting to have a patterned response at least?
Without any convention, you cannot improve. If you start to improve, it's because you have started using a convention.
I think you can play without agreed upon conventions, but not for more than a game or two. If every time you clue a card, you have no idea whether your partner is going to save it, play it, discard it, save every card right of it, discard another card, or play the card left of it...that's too random. It will be to frustrating if they do something different every time in the same situation. How could you play 10 games without starting to have a patterned response at least?
Without any convention, you cannot improve. If you start to improve, it's because you have started using a convention.