Estimates and Invoices

I work at a construction company and I'm having a hard time to understand when I'm supposed to convert an estimate into an invoice. I start creating an estimate with all my estimated costs and I include a markup for each expense. Next step would be corverting the estimate into an invoice but I'm not sure If I should convert it right away and have one invoice for the full amount of the project or if I should create invoices only when I'm supposed to charge the client a portion of the total amount.

When converting the full estimate into an invoice, I'm able to run reports that shows how much the customer still owns me but I also don't want to create invoices (with services) before receiving the payment from the customer.