Two "staggeringly incompetent" hitmen must serve a minimum of 40 years each in jail for stabbing to death an innocent student after they targeted the wrong house.
Aamir Siddiqi, 17, was attacked at his Cardiff home by Jason Richards, 38, and Ben Hope, 39, in April 2010.
The pair were paid £1,000 each to kill a different man on a nearby street.
Sentencing them to life for murder at Swansea Crown Court, the judge said few would shed a tear if they died in jail.
The pair were found guilty of Aamir's murder and the attempted murder of his parents last Friday, 1 February, after a four-and-a-half month trial.
The Siddiqi family said in a statement that they believed the sentences were "appropriate".
The judge, Mr Justice Royce, said he had no choice but to "significantly increase" the minimum term of 30 years the prosecution had asked for.
"He (Aamir) was awaiting the arrival of his Koran teacher when he rushed past his parents to open the door," he said.
"You two (Hope and Richards) came in, wearing balaclavas and making a terrible wailing sound.
"Your attack on him was brutal, savage, callous and cruel."
He said Aamir was "hacked" to death in front of his parents who were fortunate not to have been killed too as they fought in vain to save him.
"If you die in jail, few will shed a tear and many will say it will be more than deserved," the judge told Hope and Richards.
The judge went on to say the statements from the Siddiqi family were the most poignant he had come across.
The judge described Aamir as a "bright, gentle and courteous boy who was much loved by his family".
"He had secured a place to study law at Cardiff and his future was brimming with promise," he said.
After sentencing, Umbareen Siddiqi, Aamir's sister, said: "On behalf of the family, we're delighted. We feel this sentence is appropriate.
"Our brother won't return to us but this will go some way to achieving peace for all of us.
"I would like to once again thank South Wales Police, the CPS (Crown Prosecution Service), friends and family and the wider Cardiff community and Victim Support."
Aamir's sister Nishat Siddiqi later tweeted: "Am amazed and humbled by the kindness, love and support shown to my family and me in the aftermath of Aamir's murder. I will never forget."
Hope and Richards both denied murdering Aamir and the attempted murder of his parents but were convicted unanimously of all charges.
During their trial, the court heard how Aamir had run down the stairs of the family home at Ninian Road in Roath, expecting to see his imam for a Koran lesson.
Instead, he was confronted by Richards and Hope, high on heroin and wearing masks.
They wielded daggers over their heads and howled as they set upon the helpless A-level student.
Aamir's parents frantically tried to help their only son. His mother, Parveen, leapt on the back of one of the attackers as he pursued Aamir in the dining room of their home.
His father, 68-year-old Sheikh Iqbal Ahmad, tried to pin the other against a wall using his head. Both were stabbed in the process.
During the trial, the truth emerged that Aamir's killers had carried out a contract killing on the wrong victim, in the wrong house.
Richards and Hope had been paid by a businessman, angry over a collapsed property deal, to kill a father-of-four who lived in a neighbouring street.
After the murder, a huge manhunt began, and the killers' stolen Volvo car used in the crime was later found abandoned. Traces of Aamir's blood were found in the car's footwell, as were Hope's fingerprints and Richards' DNA.
After the killing the men were each paid £1,000 cash. Hope bought a pair of trainers and a laptop computer with the money.
Detectives pieced together the movements of both men before and after the killing by using the city's CCTV network and mobile phone evidence was also gathered.
Both men were arrested within days and immediately blamed each other for the killing. Hope told police he would not "take the rap" for something he did not do and drug addict Richards denied the killing.
But on the second day of deliberations last Friday, the jury rejected the killers' claims and convicted both men of the murder and attempted murders.
After sentencing, Det Supt Paul Hurley, of South Wales Police, said: "This is a substantial custodial sentence reflecting the horrific and brutal murder of young Aamir Siddiqi in his own home.
"South Wales Police would like to thank the communities of Cardiff for their continued support, all the prosecution witnesses who've played an important role in this investigation and importantly the family of Aamir Siddiqi who've shown the utmost dignity and respect throughout this process."