It is sensible for your customers to expect that you resolve their tickets within a reasonably acceptable time. If not for a solution, a quick response to their email or a call back to their phone will do. While it is indeed important for your team to respond and resolve tickets quickly, here are some means to bring in the discipline in your approach:
What is SLA Response Times
It is apparent that each ticket opened by your customers' presents a unique situation. For example, they can range anywhere between an outage in your product or a simple question about its features. So each ticket should be weighted based on their severity and responded accordingly. Thus the ticket response time gains significance.
Typically, response time is the amount of time between when the customer opens a ticket and when the agent first responds (automated responses don't count) and lets the customer know they’re currently working on it. In some cases, it can also extend to subsequent responses on the same ticket, i.e., the time between the oldest unanswered customer response and the following reply from an agent.