It's up to you : means it's your choice, your decision. You are the one who has to decide (to make a decision) selon ta convenience, cela reste ton choix et ta décision (fais en ce que tu veux, cela te regarde...)
if you give up: give up means to stop something, it's used for a habitude .. like smoking : it's not correct to say "I stop somoking " the right way is " I give up smoking". (si tu arrêtes, si tu cesses de faire telle ou telle chose...).