How long does it take to get a dnd character to level 20?

I'm curious to know, how long does the average player typically need to invest in order to bring their Dungeons and Dragons character to the pinnacle of level 20? Is it a matter of mere weeks or does it stretch out over months or even years of dedicated gameplay? The path to such a high level surely involves countless quests, battles, and character development milestones. What factors contribute to the duration, and are there any strategies or tactics that can expedite the process?