You will never have enough time to fit in everything that you want to get done. You can put a guarantee on something ‘urgent and unexpected’ getting in the way of your perfectly planned and timed to-do list.
The solution? Put your most important to-dos on a schedule, followed by the most desirable of the ‘often forgotten’ to-dos. If you put something on a schedule (a learn to stick to it), you will see that all the things that need to be done will find ways to get done. As opposed to just working down a list of whatever-come-up or convenient-now to-dos.