Checklists are the most sought after method of improving productivity by being able to manage time better on a day-to-day basis. With checklists, one can prioritise work based on whatever the need is; for me it is usually urgency, importance, or time. I personally find myself way more productive when I use a checklist. Over the past years, the usefulness of a checklist has looked like a sinusoidal wave for me. I have even forgotten that I have a checklist to go back to.
So just as productive they can be, checklists are also counter-productive.
My honeymoon days of using a checklist last usually for 3-6 weeks. After a spell of having no plan for days, I modify the way I prepare my task list. I have used productivity apps, pocket notepads, made notes in my work diary or, in an extreme case, I have created events in my phone calendar as a way to keep track of my time. But every single method fizzled out over time.
I then realised that it was not the method of keeping a check on things to do to be the problem. The tipping point when a checklist becomes counter-productive is when your purpose of the day is to complete every single task on the list rather than doing the job with complete involvement. There is a mindfulness element to it. Sudden unexpected events can never be counted for in a list every single day cause none of us can think ahead and plan. You end up having a daily battle with the task list. You no longer enjoy the work, and you find checklists to be useless. Some can have the ability to do nothing else other than the things on the list.
I think avoiding serendipity can be a huge opportunity cost.
Therefore when you try to set aside other things for the only purpose of completing the task, you have already lost the purpose of having a checklist.
But there is a sweet spot that works
I am not refuting checklists as useless. They provide direction by breaking down a big audacious goal into smaller achievable wins. In my opinion, a weekly checklist provides you with the right amount of flexibility and focus. I am not bogged down the constant need to refer to a list yet I know where I am heading, and I have the needed flexibility to allow serendipity to give me the adventure I need.