From what I understand file deallocation is important but it would not shut the system down or anything if it were not to happen.

From what I understand file deallocation is important but it would not shut the system down or anything if it were not to happen. With todays operating system the consequences would be that the file manager would not be able to organize the files. would I notice a difference in my operating system, or run out of RAM bc files are being allocated but not deallocated?