Agreed. Overheating, even if only slightly but consistently, seems to be a more common mistake when keeping garters in captivity. Even if all other husbandry factors are correct, heat stress is a killer. Respiratory infections and related immune deficiencies can be directly linked to overheating, not just dampness, dirty tanks and underheating. Any reptile vet that knows what he is talking about will tell you that many case of respiratory infection can be linked to keeping a snake too warm. This may seem contradictory since most cases call for more warmth or 24/7 elevated temps to support the immune system during an infection. Garters are naturally well adapted to cooler and less than ideal seasons. In places where heat is a problem frequently, you will not find garters thriving. Populations are stable and garters thrive even in years that are cooler than ideal.

This one of the reasons that I think it's best to have an enclosure that's big enough to ideally create a small area that is as high as 88 or even 90 degrees but also make sure that the snake can easily find a spot that is around 70 degrees during the day. That's difficult to accomplish as enclosures get smaller. Simply using heat tape and/or undertank heater isn't enough IMO. A snake that is trying to raise it's core temp will sit on a surface that is too warm, "cook" it's babies and maybe even get burned and still not accomplish raising it's core temp enough.

I'm not saying that the way I do things is the absolute only "right" way to do things but there is a lot of years, and a lot trial and error behind my recommendation of how to set up a garter enclosure. The smaller the snakes, the more relevant and higher success rate I have when I do things this way.

This is not just about aesthetics. The snakes just seem to thrive this way. And why wouldn't they? This is how they live and thermoregulate in the wild. To me this is minimal setup. Even bigger with a wider range microclimates certainly couldn't hurt.