According to the Yono all app website How Long To Beat, Fallout: New Vegas takes an average of 131 hours to complete to 100%. That number doesn't include the four chunks of story DLC the game received after launch, which collectively add another 23 hours to the game. Nor does it account for the 43 pages of quest mods you'll find over at Nexus mods. But if you've somehow completed all of that, and still haven't got your fill of the post-apocalyptic Mojave desert, then holy radioactive trousers, have I got the mod for you.
Introducing Radiant Infinium, an "Endless Questing Framework" mod designed to add an infinite number of activities to Fallout: New Vegas. Created by the modder StealthDick (settle down at the back) Radiant Infinium "introduces an infinite number of dynamically generated quests, seamlessly integrating them into the Wasteland with the usage of the Job Boards/Terminals that can be found in almost every settlement."
The types of quests Radiant Infinium can generate are familiar, MMO-style affairs including hunting animals, fetching items, and gathering herbs. There are also a couple of more specific quest times. "Kill" quests are essentially Bounty Hunts, while "Eliminate" quests specifically target higher-level radioactive creatures. There are also two types of Delivery quest, one of which Yono all app takes into account distance travelled and faction relations, while the other doesn't.
As for how the mod generates infinite quests, StealthDick explains that "Whenever you finish one of the quests, it gets added into a pool of inactive quests so it can be assigned totally different objectives in the future." Players are limited to 100 active quests in total "because there is no reason for you to have 100 active quests…ever."
All missions reward players with XP, caps, and fame. Indeed, perhaps the most interesting feature of the mod is how it ties in to locality and faction affiliation. As explained by its creator "Each job board/terminal represents the settlement it is located in" and "offers a different selection of quests with objectives based on the settlement's relations to other factions." The amount of fame you get for each quest is apparently "quite meager" but, given you can do them infinitely, that shouldn't be too much of a problem.
Personally, I've long passed the point where I found randomised quests especially interesting. Certainly, I preferred the bespoke side-quests of Starfield to its endless supply of randomised dungeons. But it's nonetheless an impressive creation from a modder, and I can see more of the appeal in a game like New Vegas, as Obsidian's RPG is packed with potential for weird stuff to happen. In any case, you can download the mod here. StealthDick says the mod supports a variety of creature mods, and Tale of Two Wastelands, which merges the landscapes of Fallout 3 and New Vegas.