I would hold at least till a TV show hits air.
Considering how many comics have been optioned for TV and movies, I wouldn't be surprised if 80% of them never make it. Sometimes it's good to sell during the initial rush, since a lot of these books won't make it to TV. Then you're stuck with it.
Very true, Iwould then ask what your ROI at this point would be compared wwith it not ever getting made. Did you invest $40 in a slab? You could break even if it doesn't make it.
as an example, I bought a couple of DMZ #1s the day after news broke for $4 each.
Sold one for $30 and one for $40. I'd rather take that, then sit on it for who knows how long in hopes that it makes it to the next step of development.
There's so much that can go off the rails in TV development. The odds are even more astronomical if you're hoping that a show gets made, and that it becomes hugely successful as well. If they make 20 TV announcements a year, and you sell all 20 in that sweet spot right after a big announcement, you will probably make more than if you hang on to all 20 for too long hoping they all get produced and all become a hit.