How do you know if a game idea/project is obsolete?

1: "Original Mechanics"

If the game has "Original Mechanics" those mechanics can be applied to OTHER games or other product. I TRY (I don't always achieve and I get distracted) to make games which are all DIFFERENT from one-another.

And yeah ... You are going to say "ALL GAMES are DIFFERENT". Which is TRUE but IF I make a "Trading Card Game" like "Quest Adventure Cards(tm)", I'm not keen on working on ANOTHER TCG. Only recently have I created a "RE-BOOT" of the older game and improved the gameplay such that the game is much more streamlined and has a simplified method of play kids can enjoy. But the "RE-BOOT" is purely a "70 Card Game". Not a TCG...

2: "Original Art"

If you have ART for the game that can help you PRESERVE the game and see if there is something still viable in that game. I (personally) like to INTRODUCE art into my prototypes (as you saw Quest AC) with art, graphic design and a more complete product than just white paper stock.

This is just me... It allows me to FOCUS and do more with something that looks prettier than just cardstock with marking on it. But that varies according to HOW serious you are. Take for example: "Fallen Kingdoms". This is one of your self-published design and you took the time to create art for the entire game.

That's how I stay FOCUSED. I remember what I've invested and what needs to be worked on to get it to the "NEXT LEVEL"! (Pun intended)

3: "Original Components"

If you have COMPONENTS that can work in multiple games... Sometimes I borrow (or steal) from my own designs sometimes pillaging a game or two for the sake of another one. This is your case where you BORROW stuff from some of your other designs.

Again I've been doing that with ONE (1) Design that has yet to see much publicity or word of mouth. In any event, borrowing Hex Tiles that I had a CLEAR direction for and moving to another game because they work better there... Is just one example of how taking something from one game leaves another game cannibalized... Hehehe. It happens.

4: "Card games and abilities"

When working with Card Games ... You often run into the "What can I do to upset my opponent?" More specifically "Take-That" cards. I find that I often run into this issue of where can I use this ability and sometimes I see it creep up in several designs. An example of this is: "Scry". Games with Decks all can have a USE for such an ability. But I find I am using it in 3 Games already and that's enough for that type of ability.

Same goes with Interactions in Card Games. There is only so much you CAN do... But WotC are experts at designing new and different cards abilities which keep on changing from one Edition to the next.

5: Lastly to answer your question(!?)

I think Mechanics that are interesting (and same goes for components too) can be used in newer ideas. Leaving old games with a whole bunch of nothing (if you design like me ... Then you don't like to repeat things) and may allow you to squeeze something new out of something old.

Is the concept DEAD or COPIED, etc. Like I said Mechanics and components can be re-used given your desired to actually USE them in something new. Sometimes you need to make that a PRIORITY and say: "Yes I WANT to use Mechanic 'X' because I feel like it is very clever..." And there you have it ... A REASON to include it.

Best of success with your designs!