OK - I’ve made a career as a project manager, and I’ve found this discussion interesting. For what they’re worth, here are my thoughts.
“Project” means different things in different circumstances - me building a bookcase is a project; me with.a team of 40 rebuilding systems and processes for finance, HR and payroll for a university is also a project. It’s pretty obvious that one wouldn’t use the same tool for both and there’s no need to spend much time explaining why. So it seems to me that the debate is much more about bookcases than finance systems and processes so that’s the direction I’ll take. Feel free to disagree.
The point’s been made (most recently be @Leo) that for many small projects, full-blown project management tools are overkill, and I think that’s true (aside: I wish people would stop assuming that “full-blown project management” equals “Gantt chart”. Gantt are very helpful in visualising, viewing, presenting a set of interconnect tasks and dependencies; they, in my long and varied experience, a lot less useful in actually planning and managing projects. But I digress). The question becomes how to decide when a task manager is OK and when something more is needed. More on that later.
The other (than choice of tool) major factor is personal working style. When organising themselves for a project, some people like to work down from a high level view of the overall goal and shape and then deriving a task list; others like to start by getting a list of known tasks down and fitting them into a pattern. And so on. One picks the tool to fit one’s needs. If I’m building a bookcase, I’ll probably go bottom up - decide number of shelves, measure, buy wood and fixings, cut and shape wood, assemble, finish. I can do all that in a task manager and I see no good reason why I shoudn’t. It’s easy and accessible and works.
If I’m planning a major project I’ll go the other way - define the goals, identify resources, major constraints (time, people, money etc), major dependencies and risks, draft a high level plan and refine recursively until there’s something actionable. I can’t do that in a task manager. I’ll generally use mind mapping at the first stage and then expand nodes of the map using notes applications. Only at the final stage (something actionable) will I use “project management” software.
Out of my actionable plan come sets of tasks. I’ll manage my own in a task manager, because now I’m running a task list, as is everyone else on the project. Periodically, we reconcile the status of our tasks lists with the overall status and needs of the project. We don’t combine the two (aside: I don’t want automatic integration between tasks lists and project data. I know many people do, but my own experience is that (a) people find themselves working around the integration, either because ti doesn’t work well or because they’re deliberately trying to fudge the data and (b) there’s no substitute for the critical intellectual process of actually looking at where you are and what you have to do.).
So - my conclusion is:
Use a task manager when you know the overall shape, goal, structure of your project, whether that’s in your head (bookcase) or written somewhere in a plan.
Use something else when you don’t.
That turned out longer than I intended.