With the SpiceCRM SLA Manager, you can define Service Level Agreements. They can be generic or related to any parameter of a ticket or they can be customer-specific. Based on the SLA the expected response time, as well as the expected resolution time, will be automatically calculated.
This calculation of course also considers service calendars as defined in the SLA. A simple indicator will help your team to focus on the tickets based on priorities and also the guaranteed service levels. In case you are not able to resolve issues in time the system also provides an option to prolong tickets with a justified reason to extend the timelines.