The amount or degree of heap memory management required in a program is a consideration that depends on the complexity and expected runtime duration of that program.
When heap memory is initialized at the start of a program and remains largely unchanged after it is initialized, little heap management will be required. It may be acceptable to simply let heap memory exist until the program exits. The free() function may never be called in such a program.
On the other hand, for programs whose complexity is large, or where heap memory is heavily used, or where the runtime duration is hours, days, months, or even years, heap management is essential. A program that controls, say, a banking system, a fighter jet, or a petroleum refinery might have catastrophic consequences if the heap for that program is not properly managed, causing the program to terminate abnormally. The bank may suddenly show a pile of money in your account or take it all away...