Charles Rampant
Adventurer
I've found that when I run pre-made adventures that conversations become much slower. I have to pause and read the NPC description and the plot goals before and during each time the players roleplay with someone that they meet. This is in addition to spending a lot of time trying to read and memorise the adventure between games. However, I am hopeless at dungeon layouts and suchlike, so I prefer to steal premade ones rather than make my own.
I can echo the suggestion upthread to use premade settings but your own adventures; that seems to be the sweet spot of time saved. Using the Realms, for example, results in a reasonably deep-yet-generic setting that you can swiftly read up on enough to locate your adventures, and will save you a lot of time spent trying to create your own deep-yet-generic setting to use. You miss out on some fun that way, though.
I can echo the suggestion upthread to use premade settings but your own adventures; that seems to be the sweet spot of time saved. Using the Realms, for example, results in a reasonably deep-yet-generic setting that you can swiftly read up on enough to locate your adventures, and will save you a lot of time spent trying to create your own deep-yet-generic setting to use. You miss out on some fun that way, though.