Open Quotes in the sidebar. Every request is here, newest first. If you know the Orders screen, you already know this one.
Filter by status along the top, search by customer on the right.
The links above the list filter by status, and the count next to each tells you how many are waiting. Pending is the one to watch.
The search box looks through customer name, email, and company, so you can find a quote when all you remember is who sent it.