Preheating a toaster oven is generally not necessary for all types of cooking, but it can be beneficial for certain recipes and foods. Whether it's considered "sane" depends on your specific cooking needs and preferences.
Toaster ovens are designed to heat up quickly, and they often reach their desired temperature faster than traditional ovens. For simple tasks like toasting bread, heating up leftovers, or baking small items, preheating might not be necessary. You can simply set the toaster oven to the desired temperature and put your food in immediately.
However, for more precise baking or cooking, especially when following recipes that require specific temperatures, preheating can be beneficial. Preheating ensures that the oven reaches the correct temperature before you put the food in, leading to more consistent and accurate results.
In summary, preheating a toaster oven is a personal choice and depends on the type of cooking you're doing. For basic tasks, you can skip preheating, but for more involved recipes, it's a good idea to preheat the toaster oven for better cooking outcomes.