I think some people are confusing depreciation with amortization. No you can't depreciate property that you do not own. But yes you can depreciate or amortize improvements you make to leased business property. Whether you are conducting a business or not is a question you must resolve. But any improvements you make to leased business property are yours to amortize or depreciate. "Leasehold improvements" are linked to your business, not the property.
