That's the point: while there might be just 1 team member with a clear understanding of the effort, everybody gets to pick an estimate based on their own knowle

That's the point: while there might be just 1 team member with a clear understanding of the effort, everybody gets to pick an estimate based on their own knowledge of the subject matter, even if they know nothing. The exercise of just enumerating in a couple minutes all the steps to complete such a story gives everybody, including the one who is going to do the job a clear idea of the effort or whether they need more information before proceeding. Btw, while Scrum is great for software development, they are not ideal for maintenance and/or infrastructure management where a defined process such as waterfall might work better. Trouble tickets and bug fixes should be kept outside the sprint unless they become stories.