Another place to look on the last tax return you claimed the home office on, is the form 4562 titled "Depreciation and Amortization Report" that prints in landscape format. Simply add up the amounts in the prior year depr column and the current year depr column to get the total depreciation taken.
Be aware that recaptured depreciation is not included in your capital gains exclusion. It gets added to your AGI and is part of your taxable income.
