Although I have never accessed this service, my travel agent had a client lose three days of a trip because the information on the Timatic system was outdated. I'm a big fan of the belt and suspender approach, since rules change so frequently: In addition to the obvious government websites, I also call airlines and consulates if the rules are not clear.
On my last trip to Australia, my agent was very concerned that the airline might stop me, even though 6 month validity wasn't necessary. Two weeks before departure, I made an appointment for an expedited passport on the basis that I needed visas for this trip. It was a dream process, much to my surprise, and I had a new passport in hand in 24 hours.