I am a VERY small scale breeder. My rats are always PETS first.
I do not breed for profit, and I keep my numbers low because it would be unethical to overcrowd the enclosures.
I have other, smaller units for quarantine or whelping (raising babies), but these are the main enclosures, and my play area.
Staying so small also allows me to ensure I've spent the right amount of time with each individual rat in my home before I send them off to be pets in the homes of adopters. It helps me to avoid becoming overwhelmed, and not keeping up with my obligations to my pets.
When you adopt a TKIS rat, you can be sure your pet has been hand reared and socialized by myself AND my family, as we all play a role in caring for them. As we spend the bulk of our time in and out of our bedrooms, that is where the rats are housed, so we can give them the most attention they can get.
I do not employ bin cages, though I have no issue with those who do so (properly). My personal preference is Midwest Critter Nation DCN, or Prevue Hendryx 528 or similar.