When to advertise property?

[Ian C.]

Under contract for my first duplex. Subject to home inspection, bank inspection and financing. Hoping for smooth sailing but I know a lot can happen so trying not to count chickens before they hatch. However, wanted to know experiences of investors in the timing of their rental advertising. I want to get tenants in ASAP for this tenant-ready, but presently unoccupied, two-unit -- so I have income coming in the same month as I have expenses coming in. When is the right time to begin posting advertisements, craigslist, etc?