Tasty vs Mild vs Mature Cheddar Cheese
According to Dairy Australia, an Australian industry association (emphasis added):


  Cheddar Classifications
  
  
  Mild Cheddar - matures for one to three months. 
  Semi-matured - matures
  for three to six months. 
  Matured or tasty - matures for six to 12
  months.
  Vintage - matures for 12 to 24 months.