@JeremyECrawford do PCs need to take a long rest before leveling up? I've assumed that but I haven't seen anything in the book about it.
— Al Houghton (@HoughtonAl) April 28, 2016
No rule requires a rest before leveling up. The DMG (p. 131) contains a variant that requires days of training. #DnD https://t.co/ab1SkVHisZ
— Jeremy Crawford (@JeremyECrawford) May 3, 2016