Jon $$Jetset$$ Jones has requested your advice on the potential tax ramifications of the proposed sale of his Beverly Hills, California condo. Jon acquired the condo ten years ago for $$500,000$ and it has a fair market value of approximately $$1,000,000.$ Jon considers this his primary residence. However, he also owns residences in New York, London, and Tokyo.

He estimates he spends $120$ days per year in the Beverly Hills property, more than any other individual residence, but less than the total days spent in the other residences. He has consistently claimed property tax $$homeowner$$s exemptions$$ on the Beverly Hills and London properties. He has been a registered voter in Beverly Hills for the last eight years but has not actually voted in any election. He carries a New York driver$$s license. The address on his Form $1040$ for the past $5$ years was that of his attorney$$s New York office.

In a letter to Jones, explain what tests the IRS and Courts have used in the past to determine what qualifies as a $$principal residence.$$ Include in your letter what facts or other documentation would you like to see that could strengthen the argument that the Beverly Hills condo is his principal residence?