Sprint planning is meeting that team holds together answering one question: What are we planning to accomplish in the next sprint?
When planning a sprint take into account few key points:
- velocity of the team, for example, 80 points per sprint
- capacity of the team, for example, is everyone from the team available 100% of their time during the sprint
- priority of backlog items that are defined by product manager
If you have at least 1 sprint worth of prioritized and groomed product backlog, sprint planning meeting shouldn't take more than 30 minutes.
While it's ok to occasionally groom 1 or 2 tickets during sprint planning meeting, it is not recommended to combine sprint planning with backlog grooming activities.