Setting History Tracking

For auditing reasons we recommend that you select history tracking on fields used in depreciation calculations. You can then view this information from the History related list for that object. For instance, to set field history tracking on the Applied Depreciation Method object:

1. Click Setup | Create | Objects | Applied Depreciation Method.
2. Scroll to the Custom Fields & Relationships section.
3. Click Set History Tracking.
4. Select the checkboxes of the fields that you want to enable tracking for.
5. Click Save.

See the Salesforce Help for more information.