Hello, Mepomena. 

In QuickBooks Desktop, estimates remain active even after you have converted them into sales orders for a few reasons:

• Estimates serve as a historical reference for your business. They allow you to track the progression of a transaction from the initial estimate to the final sales order. This can be useful for auditing purposes or for reviewing past transactions.
• Estimates can be used for future planning and forecasting. By keeping estimates active, you can easily refer back to them when creating new sales orders or invoices. This helps you maintain consistency and accuracy in your sales process.
• Sometimes, estimates need to be revised or updated before they are converted into sales orders. You can easily change estimates without affecting the sales order by keeping them active. This flexibility allows you to adjust pricing, quantities, or other details as needed.
• Estimates often serve as a formal proposal or quote that is shared with customers. By keeping estimates active, you can easily refer back to them during customer interactions. This ensures you have all the necessary information readily available when discussing the transaction with your customers.

While it is possible to delete or close estimates once they have been converted into sales orders, it is generally recommended to keep them active for the reasons mentioned above. However, if you prefer to remove them from your records, you can do so by manually deleting or closing the estimates in QuickBooks Desktop.

Here's how:

1. Go to the Customers menu and choose Customer Center.
2. Select the customer's name that has open estimates.
3. From the Transactions list, look for and open the estimate.
4. Click the Mark as Inactive or Delete button.

I've also got a helpful article for future reference. This article contains ways to track customer transactions in QBDT. You can learn more about organizing your cash flow, sales, receivables, and profitability through this article: Customer transaction workflows.

I'll be here if you have any other questions or concerns about estimates. Have a great day!