By taking the maximum odds bet every time you make a pass or don't pass bet, you maximize your winning potential and lower the house edge on your overall wager.
Odds bets usually have a maximum bet amount that is some multiple of your pass or don't pass bet - 2X, 3X, 5X, etc. However, odds bets can only be made on top of other bets, so, if you make an odds bet, the house still has an edge (albeit a diminished one) on your overall wager.
Odds bets are somewhat unique in that they are truly fair - the house has no edge at all on these bets.