I have been relying on them for years - so I should know. When I am overwhelmed with numerous miscellaneous tasks, at a risk of forgetting some of them, the first thing I do is get hold of a post-it note, list them out, add to them whenever I remember a new task, and strike each off whenever it gets done. Sometimes it feels good to reduce the enormity of chores to a few words in a paper and it is liberating when each one is removed off the list and the list reduces to zero (which is theoretical and optimistic because by that time ten new items would have been added).
Many a time I have observed that the best managers of time are the ones who maintain their to-do list well. Each one has his own method of managing his tasks - not necessarily using post-it notes. Some flag their emails (even set reminder alarms on them) so that they know which items need to be followed up, and when. Some paste Turbo notes on their computer desktops(Turbo notes also can have alarms).
I have also known people who never keep track of their pending tasks (at work or home) and always complain that they do not have enough time. They always need someone else to nudge them to do their work, which is quite irritating. I may be wrong, but I think listing out the tasks and prioritizing them would help a great deal, almost "half the job done", but convincing these people about the efficiency of todo lists and making them follow it is a herculean task in itself!
In addition to listing out tasks, even the smallest ones, and prioritizing them, we need to plan how much time to spend on each. If it doesn't finish by then, move on to the next. Otherwise, an entire day would be wasted by attending to one job, which would not get completed, and the remaining ten would get postponed to the next day.
All this would sound wonderful theory for those who haven't tried it.
I have, and I know it works.
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