Differences between WIFE and GIRLFRIEND

Vova wrote to his daddy: What are the differences between WIFE and GIRLFRIEND, Dad? 
His Daddy replies: My dear, Wife is a TV. Girl friend is a HandPhone. At home watch TV. Go out, bring HandPhone. No money, sell TV. Got money, change HandPhone. Sometimes enjoy TV, but most of the time play with HandPhone. TV is free for life. But HandPhone, if you don't pay, services will be TERMINATED!!! But u should be careful with both, my dear son...^^