I'm not bored of Halo in the least. Each entry has been high quality, and the latest was one of the best IMO. I can't wait to see what 343 has in store for Halo on the Xbox One.

Probably when the quality of the game's storytelling begins to fade. People don't understand how Halo was the start of mainstream FPS popularity on home consoles of the 21st century. The 90s had Doom, Half Life, and Goldeneye 007. The game still maintained the epic storytelling, but it seems to be heading into a totally different direction do to 343 having their take on the series. But Halo is a brand that will eventually has to come to an end. Microsoft shouldn't risk making Master Chief their Mario. Bungie are making Destiny and using all their talent that made the first 3 Halo games great. Destiny will be an instant classic. Just wait and see.

I don't really care much for the story. The multiplayer is probably what makes people come back for more, same as the Call of Duty games.

Mmm, might take a while. just look at call of duty

Yea, I would see why. You don't get that much involved or much of the story just playing the demo.  (Like how I had to start 'The Hobbit' several times before I got into it.  As something like the first 30-90 pages are just some crazy tea party.  I had to get through that before it became interesting.)

There really is an in-depth story, characters and a whole science fiction world.  But if you don’t like playing the shooter part, it’s probably not worth it.

I think I was about 75% finished with Halo: Reach before I thought I was good enough to actually enjoy the game.  It takes time to get into it.

If you like anime/Sci-Fi you might want to check out Halo: Legends for some back story.   But you are seeing years of story compressed into a narrative.

Never... at the least the single-player part... give me more.

When people stop buying it.

In my case, it happened after about 8 minutes.

Never, Halo is one of the few series that retains its originality and freshness, compared to the liked of Mario and COD.