With CATIE, you can conduct multiple cases at the same time, reusing the same resources. In many situations you'll want to perform an IP lookup and at the same time perform a screen capture for another case. Both situations are important...so what do you do? Starting a new case while the old case is still running allows you to do just that. The number of instances you have is based on your license, but in many cases you can order more instances if you need them.