You identify the scope and nature of a project. Design the project plan and assign resources and begin the process of real work and plan executions. Many tasks follow a predicted path and glide down the slope toward completion. Others hit speed bumps and issues arise. If you only encounter a few issues along the way, they are fairly easy to manage with emails and spreadsheets. The issues still require special attention and follow up costing time and energy, but manageable. What happens if you 130 issues arise in a short period of time (as is often the case in software development and bug fixes)? Spreadsheets and emails won’t cut it. In no time you lose track of events, issues and milestones. I am pointing out the obvious. But I have counseled hundreds of project managers using outdated tools and methods to track issues. Maybe project management and issue tracking software/tools cost a little money (others cost a lot of money), but believe me, they will pay for themselves many times over in saved projects, efficiency and ultimately the bottom line.