Do I need to complete self essment?

I am an employee and the taxes are taken by the employer thru PAYE. I have 2 savings account but the interest earned is just few pounds. I am being sent a Self essment letter by HMRC for the last 2 years. My friends say that I should not file the return as my taxation is very clear, does that mean I should ignore the notices being sent by HMRC or I am legally bound to file the return even though my taxation is not complex ?