Old tax law regarding home office deduction
New, improved tax law
You could only deduct a home office if
The home office was the principal place of work
The home office was used exclusively and regularly for work
These requirements meant most could not claim the home office deduction
A traveling salesperson probably could not deduct a home office because the customer's site constituted the "principal place of work"
Now you can deduct your home office if it is used for substantial administrative or management activities and there is no other fixed location for such activities available
Home office still must be used exclusively and regularly as a home office
New law effective beginning in 1999