The Hatton Garden raiders have been held in a high-security prison, sometimes only seeing 30 minutes of daylight a day, a court has heard.
Since their arrests in May last year, they have been on remand in Belmarsh prison, known for housing some of the country's most notorious criminals.
The gang - including men who were involved in the Security Express and Brinks Mat robberies - breached the vault at Hatton Garden Safe Deposit in central London over the Easter weekend last year.
Their trial was specifically held at Woolwich Crown Court to accommodate the high-risk status they were granted after being arrested.
But, making submissions on behalf of their clients, lawyers representing the men found guilty of the £14 million burglary - the largest in English history - asked Judge Christopher Kinch QC to take into account the conditions of their remand when he sentences them.
Nick Corsellis, defending Carl Wood, 59, said: "Clearly the motive for being involved in this was financial gain."
The jury found that Wood was a thief the Crown identified as Man F in CCTV on the nights of the raid.
The Crohn's disease sufferer was part of the gang which gained access to the building on the first night but, upon discovering a locked fire escape, when the group returned on the second night, he abandoned his accomplices.
Mr Corsellis said time in Belmarsh had been particularly hard on his client, and asked the judge to take into account the fact that Wood's inevitable jail term will mean that he will "not see" his ailing parents again.
He said: "His remand in custody had been particularly difficult because he, and they (the other men), are in double A category.
"That means that they are housed in a cell on their own. And they are given one hour of exercise a day. It is very rare that that is achieved - half an hour at best. Half an hour of daylight."
Adding that this had psychologically affected his client, Mr Corsellis went on: "That means they are not able to participate it the community in prison, and the remand in custody has been difficult to bear. And their remand status is likely to remain as is, for the foreseeable future."
On behalf of Hugh Doyle, 49, the court was told that, over the last eight or nine years, he had made an effort to change his life and turn away from crime.
Paul Keleher QC, defending, said: "He has become an honest man, but he has made one big mistake, and that is what he is here to pay for today."
He also asked the court to take into account the fact that Doyle spent six months in Belmarsh, before being released on bail once the Crown dropped the burglary charge against him.
Mitigating on behalf of William Lincoln, 60, Dante Leccacorvi asked the judge to take into account the fact that his client had a very limited role in the conspiracy.
He said: "He had a very distinct role and that was to conceal the proceeds of this crime on a short-term basis."
Mr Leccacorvi also listed Lincoln's ailments - arthritis, high blood pressure, chronic sleep apnoea - and said that, while these were not life-threatening, they had made his time in custody harder that it would otherwise had been.
All of the defence barristers argued that their clients should not be made the subject of Criminal Behaviour Orders.
Arguing for these to be imposed, prosecutor Philip Evans QC said: "These defendants, over a sustained period of time, have planned the very significant burglary in which they broke into the premises at Hatton Garden.
"They stole from it, they took those people's possessions - and large quantities of them - away and disposed of them."
Adding that it was possible the men had also melted down the goods, or even taken them abroad, he continued: "These are sustained actions, and it is overwhelmingly likely that the victims of this offence would have been caused harassment, alarm or distress."
Ringleaders John "Kenny" Collins, 75, of Bletsoe Walk, Islington, north London; Daniel Jones, 61, of Park Avenue, Enfield, north London; Terry Perkins, 67, of Heene Road, Enfield, and the group's oldest member, Brian Reader, 77, of Dartford Road, Dartford, Kent, pleaded guilty to conspiracy to commit burglary last September.
Wood, of Elderbeck Close, Cheshunt, Hertfordshire, and Lincoln, of Winkley Street, Bethnal Green, east London, were convicted of conspiracy to commit burglary and conspiracy to conceal, convert or transfer criminal property after a trial.
Plumber Doyle, of Riverside Gardens, Enfield, was found guilty of concealing, converting or transferring criminal property between January 1 and May 19 last year.
Reader has been absent from the sentencing hearing after falling and suffering a stroke in Belmarsh.
All six men are due to be sentenced on Wednesday, when Judge Kinch will also decide when Reader will be sentenced.
Perkins's daughter, Terri Robinson, 35, of Sterling Road, Enfield, pleaded guilty to concealing, converting or transferring criminal property, alongside her brother-in-law Brenn Walters, 43, who is also known as Ben Perkins.
They will be sentenced for their roles in the conspiracy on March 21.