&tldr; You should probably be doing Kanban instead of Scrum and you might not need to spend as much time estimating things.
Scrum seems to be the defacto standard of software development here in 2017 (well 2016 at least). While it might be able to be credited with moving the industry away from the typical waterfall process I would contend that it's often implemented poorly as simply a miniture waterfall. While that model might work well for some situations, there are more modern alternatives that work better with
As your team begins to adopt continous development practices and works towards continous delivery techniques it might become obvious that Sprints are no longer necessary and are simply arbitraty time periods often for reporting purposes. Focus shifts to keeping a prioritized list of work that needs to be accomplished and staffing appropriately to prevent that list from becomming too long. This may mean adding or removing people depending on the proje