It's good practice to add at least a date modified field to your records, but hardly a requirement. I suggest that you consider your design and ask yourself:
Is it important to know the time the record was last modified?
Is it important to know the date it was laste modified?
Is it important to know that it WAS modified?
Is it important to know WHO modified it last?
As you answer such questions, it should become pretty easy to decide what fields of this type you'll need.
Case in point:
We have an invoicing system here where I work. Each invoice is created and within minutes it is printed. Such invoices are never modified after printing except to void one in order to issue a new one to correct an error. Thus, none of the "modify" auto-enter field options are useful. But we do want to know who created the invoice and when (date and time ) it was printed. Thus we have fields and scripts to record that info in our invoices table.
And if you later change your mind as your understanding of database design and the needs of your project changes, it's a simple matter to add such fields in at that point.