It is beneficial to cover your grill, at a minimum during the cold weather season. A grill cover protects your grill from the weather elements. Keeping rain and snow off of your grill is key to long term care, and it will also ensure that your grill doesn’t develop premature rust on any of its parts. Indiana humidity and moisture can build up on your grill and get trapped under the cover, and actually lead to rust and damage if you never take the cover off and let it breathe.
Cheap-o covers last only a year or two. A good cover will last five years or more. All the plastic or vinyl ones can crack and fell apart in two to three years. The canvas covers rotted in a few years. The best were canvas laminated or impregnated with polyurethane or PVC.