Tactics
At rubber the goal is to win the most points over a series of hands and it is important to make contracts to try and win the rubber and get the bonus. Over tricks don't matter, even less than at IMPs. Balancing over low level contracts is not as attractive because unless you can make contract you have little to gain and may force the opponents into a higher scoring contract. Sacrificing can be expensive and only preserves the current state rubber as far as points below the line go and a 500 point penalty is possibly worth as much as winning the rubber.
At rubber every hand is affected by the context of the score and there are many different factors to consider and weigh up. You need to be constantly aware of not just the vulnerability but what legs (part-games) both your side and the opponents have. This affects what bids you make and the meanings of bids. Game may only require 2♥ so it is worth stretching to bid it with a weak hand but not to go higher with a strong hand unless 6♥ is a reasonable chance. Part-scores like 40 and 60 are highly worthwhile as one can make game with two of major or 1NT respectively on a later hand.
This is very different from duplicate bridge where each part-score and game are worth fixed amounts and each hand is an individual battle over points.
Read more about this topic: Rubber Bridge