I checked on this with my accountant last year and he said if you buy the timeshare as an investment property then you are able to deduct many things and if you bought for personal use and its going down in value then some cost may be deductable under the idea of perserving your investment value. Your best off consulting with an accountant who is familiar with the laws in your state and you can be sure that if your making money off the timeshare then it will be taxable!