There's no set, standard time for meditation. Most apps provide sessions of between 10 and 30 minutes; you can go on a retreat and do it for nine straight hours; or you can simply push back from your desk, close your eyes, and breath for 45 seconds.
Of course, it can feel haphazard or rushed to do a short meditation, especially when we've recognized the benefits of sitting for a longer period of time. It can feel like we're trying to half-ass it and not commit to the process. But there are real benefits to making short meditation a part of our regular practice.