Sometimes you need to import a part or an assembly or maybe you are using mirror part. Have you ever thought about what template is being used or wanted to be able to change template? Or maybe you get a question which template to use, when you actually want to use the same one every time to save time and not having to chose one every time. This is how you set the default templates in SolidWorks.
Go to Tools > Options > Default Templates
As you can see, these are the templates used when SolidWorks does not prompt for a template. You also have a setting in the lower section where you choose if SolidWorks always should use them or if you should be able to choose the template when needed. This way you could chose the setting that suits you the best.