Do I need another diaper bag?

For those of you with 1 + twins, would you recommend a 2nd diaper bag? We have one for our 16-month old, and figured we'd need another for the twins. Just wondering if I should spend the money, or if 1 bag is ok for all 3 (is that just totally unrealistic???)

FWIW, we don't typically go out a lot with our LO. We use it for when we are going out to eat, or when we go on playdates or something, but generally do not go places too often, and figure with the 1+twins we won't be going out much anyway!