The ideal amount of time to spend in Las Vegas to see the best of the city in 3-5 days. His allows plenty of time for exploring downtown, gambling in the casinos, relaxing by the pool, and enjoying the exciting nightlife. However, if you are looking to stay longer, there are plenty of things around Las Vegas that can fill your time. Keep in mind, if you plan on drinking and partying for most of your trip, 3-5 days will be more than enough time for Sin City.