Keep all of your receipts and invoices and include the whole cost of the enhancements or additions with all your extra medical and dental bills on Line 1 of 1040 Schedule A. The easiest way to claim a home-office tax break is by using the usual home-office deduction, which is predicated on $5 per square foot used for enterprise up to 300 square ft. The “regular method” for deducting a home office includes calculating the proportion of your home that’s used for business. Money you spent on mortgage interest or energy-efficient upgrades can come again to you at tax time.…