Many todo applications, such as Things 3, Omnifocus 3, and Todoist, have tag support. Tags can be anything that give context to a specific task or project. In fact, in a pure GTD system they used to be called Contexts. But tags are more flexible since each task can have multiple tags.
One of the things I’ve struggled with the most is how to implement tags in a useful way. Initially I found myself tagging things based on their subject area, such as school or development. This ended up just duplicating the project name. One of the older techniques was to use tags (aka Contexts) to identify where or when certain tasks can be completed. This made it possible to filter out tasks that you could do based on where your were or what your current capabilities were. For instance, you could tag items as “Errands” that were things you needed to do while you were out of the house. Another popular use for tags is setting the intensity level of the task. By nature some tasks take a lot more effort, both physical and mental, than other tasks. Many people like to accomplish their harder tasks early on in the day and save the easy ones for the end.
The system I’ve implemented has four tags: quick, low focus, high focus, and waiting.
Quick tasks are defined as any task that can be done in a few minutes, but never more than 15. These are things that I really have no excuse for doing when they’re created, but I can’t do because I’m doing something else or am in the wrong context to perform them. Later on when I review my task system, I will usually knock out a few of these tasks so that I can gain some productivity momentum, which I find very important to staying productive.
Low focus tasks are just like they sound: they don’t require my full attention or energy. These might take longer than quick tasks, but I can complete them in a wider variety of environments and conditions. I will usually complete these after my quick tasks to maintain my momentum. I can also sort of do this tasks while doing other things.
High focus tasks require all of my attention. I really need to focus while doing them, and I can’t have any outside influences that might distract me. This means no videos on in the background, and if there’s music on it has to have no lyrics. I also usually need to be in a certain state when I complete these tasks where I am well rested and energized. They also need longer blocks of time compared to the other tasks. A single high focus task might take as much as a half day to complete.
Waiting tasks require someone’s else’s response or work before they can be completed. This could be an email response, a phone call, or an in person meeting. Whatever it is, I cannot complete it until they get back to me. This allows me to filter them out of my system and ignore them until I need to, which reduces how much my brain thinks I need to do.
These four tags cover basically every single type of task that I encounter. For me it’s great to use these tags to filter the system to figure out what can be done based on how I’m feeling or where I am. In a sense it’s a combination of the previous two tagging systems I’ve described. However the nice thing about tags is that they can be customized to everyone’s individual needs and change over time.