To support your claims, you must maintain certain records, including:

• Receipts for all expenses incurred, including those for depreciable assets.
• Diary entries for small expenses ($10 or less, totaling no more than $200), or expenses for which you are unable to obtain any form of evidence, regardless of the amount, such as stationery.
• Detailed phone bills accounting for all work-related calls. If you do not have itemised bills, you can reasonably estimate call costs using a four-week diary records and relevant telephone bills.