Signs your current PC case is failing you and your system

The PC case protects all the vital internal components inside your PC, be it the graphics card, motherboard, or cooling fans. It's an important job, but not all cases are created equal. Some have advanced features such as dust filtration monitoring, the latest USB standards for front-facing I/O, and support for the largest radiators you can buy. Others are more affordable and may be slightly limited on what they can be used for. But how do you know when you should upgrade or replace your old PC case?