Many students still use printed diaries and calendars. The brain in the process of writing processes information and remembers when a person writes by hand. There are many studies on this topic that you can find in the public domain.
There are thousands of different free templates and April Printable Calendar grids in the world for every taste. There are strict and classic ones, there are multi-colored ones with photographs, there are dated ones, and there are no dates.
There are even whole communities of people obsessed with planning. Each of them is trying to create the best scheduler for their tasks and goals.