As a general rule it is wise to have your alignment checked; 
 

• every 12,000 – 15,000 miles or

•  at least once a year

   

However, it is also highly reccomended when;

• You knowingly hit a kerb or pothole 

• New tyres are fitted 

• Steering and suspension components are replaced 

• The vehicle has been involved in any form of accident or collision

  (If the vehicle as been to a repair centre it may have had the alignment checked - just ask for the printout)