According to Pablo Hidalgo and the Story Group, Luke Skywalker trained on Dagobah for about six months before leaving to face Vader.

Saw an interview with Hidalgo where he discussed this a few months ago. He also stated that time moves much quicker on Dagobah, as it works differently on planets that are extremely strong in the force. So do we know how long the total timeline of ESB is? Because the Millennium Falcon traveled to Bespin on sublight engines, which would be quite a long trip, even with Bespin and Hoth being next-door neighbors, astronomically speaking. via /r/StarWars https://ift.tt/TWfNyuq