Improper caulking can lead to leaking, wetting, staining, mold development, moisture smell and water damage. There is one primary reason to re-caulk it is to change old discolored and molded caulk.

Also, re-caulking or calking can protect from absorbing water in places like under the walls and the floors where mold can grow. The cost of caulking or re-caulking much less than tile replacement or water damage repair and often only re-calking bring back to old shower a new and fresh look.