After retiring from royal life back in 2017, the Duke has spent most of his time between Wood Farm on the Sandringham Estate and Windsor Castle.
"The Queen feels the Duke has earned a proper retirement," a source told the Express.
"She knows him too well, if he was still at the centre of royal life he'd feel he had to be involved.
"Being at Wood Farm means that he's not too far away, but far enough to be able to relax."
Meanwhile, editor of Royal Central, Charlie Proctor told Daily Star Online that Prince Philip hardly spends any time at Buckingham Palace.
"Unlike most married couples, The Queen and the Duke of Edinburgh often live miles apart."
He continued: "This is down to the fact that he is now retired and would rather live in one of his other homes.
"Buckingham Palace has always been viewed as a workplace by the Duke.
"It is in the middle of noisy central London, and perhaps doesn't offer the same peaceful tranquility as Windsor Castle of Sandringham House.
"As our 93-year-old Queen is still working, this is where she will spend the majority of her time in her workplace."
WATCH: Moment Queen Elizabeth Sweetly Broke Protocol by Stopping to Accept Flowers