This is a simple test, which detects changes in the neck of the womb, which may lead to cancer in later years if not treated. It is usually performed by the practice nurse, or your doctor if you prefer. The criteria for routine smears is currently undergoing change. Women are being screened from 25 years to 65 years. For those aged between 25 years to 49 years, routine screening will be performed every 3 years, for those aged between 50 years to 65 years, routine screening will be performed every 5 years.