When I start creating a game I want a time goal for me to finish the prodject. I want a good reasonable amount of time. I would adjust it if my game is super small etc.
If you're making a simple game, like a tycoon or obby, it can take as little as a few weeks with small updates from time to time. However, if you're making a complicated game, i.e. Elemental Battlegrounds, Booga Booga, or Jailbreak, it can take up to months or maybe even a year to complete it. And they're still updating their games. If I were to give an average for how long it takes to finish the basic points of a game on Roblox, I'd estimate it'd take somewhere from 1-2 months.
i would say it took me about 2-3 months to add all the details