Looking at replacing Crickets with Dubia and I see many start a Roach Colony. Our girl is about 5 months old so she is eating a lot right now. What do you do with the colony when the Dragons get to around 18 months and is eating much more greens then live protein. I would assume you don't need a colony anymore.
You can keep the colony going. Maybe bring the temps down to room temp by removing the heat source so they don't breed as quickly. You can also give away some of them as the colony grows if you have people in the area who want them. I've given some to my vet to help rebuild her colony. Your dragon won't stop eating them completely though so she'll always have use for a colony to an extent.
You can sell them (online, Craigslist, classified page here) if you get over populated. You can also control the population by culling out the males/adults. Mine also help dispose of produce and veggie scraps in the house.