The phrase for pre-baking a pastry case is "baking blind".

Generally, you pre-bake the case when the ingredients are already cooked, and you are composing them into a complex tart, or when you are using a "custard" filling that would possibly result in soggy pastry.

If you are making a "closed top" pie, you might still want to pre-bake the base case to prevent the pastry from becoming soggy when it contacts the filling, or you might play a blowlamp flame across the inside to avoid the problem.

Much of what you do also depends on the type of pastry you are using. The best thing, if you are unsure, is probably to search out similar recipes and use those to form your ideas.