There is a 17-year gap between when Frodo Baggins inherits the One Ring from Bilbo and when he finally leaves the Shire. This period is crucial for Gandalf to research the true nature of the ring, confirming its identity as the One Ring. Gandalf spends this time traveling, gathering information, and searching for Gollum to verify his suspicions, which delays Frodo’s departure until the danger becomes imminent.