Sample Due Diligence Letter – The following Sample Due Diligence letter is sufficient for the purpose of meeting the Due Diligence requirement. Perform due diligence for hard money loans to ensure informed decisions.Assess lenders, terms, and risks for successful borrowing. Performing due diligence is important for both the buyer and seller involved in a commercial real estate transaction. Due diligence is required 30 to 120 days prior to escheatment. Due diligence in real estate is a period of time during the homebuying process, typically after an offer is accepted and before closing. It's an initial deposit that is customarily submitted with an offer, and part of the contract, to purchase a house in Maryland.