Final answer:
Deleted fields in Salesforce are kept in the Recycle Bin for 15 days, after which they may not be recoverable unless specifically restored within this period. The total duration is 30 days.
Step-by-step explanation:
In Salesforce, deleted fields are kept in the Recycle Bin for a duration of 15 days after deletion. However, it's noteworthy to mention that if the Recycle Bin's storage limit has been exceeded, items might be removed prior to the 15-day mark. If you need to restore a deleted field, you can do so from the Recycle Bin within this time frame. After 15 days, or if deleted manually from the Recycle Bin before the 15 days are up, the deleted fields may not be recoverable.
These deleted fields in the 'Deleted Items' folder are kept for an additional 15 days. Therefore, the total duration that deleted fields are kept in Salesforce is 30 days.