There's several viewing guidelines you can follow for TV:
http://en.wikipedia.org/wiki/Optimum...ewing_distance
I have a 55" TV, and thus sit about 10 feet away for the best experience. I hate normal glasses (non-sunglasses); I've worn contacts since the 90s. At the height of my serious medical issues in late 2012, 2013, and early 2014, the blind spots in my vision made me mostly useless for video work. I still have them (better, but not gone), and have to be extra vigilant when looking at a video. It's the main reason I mostly do hobby projects these days, to get used to the new normal in my life. (Working full-time is still not possible for me. Even typing on this forum can still be challenge. Lots of people assume I'm back to normal, but I'm not.)
The most bothersome errors are
- chroma noise
- chroma bleeding
- grain
- non-content movements (vertical jitter, timing wiggles aka horizontal jitter, etc)
Some people are far too anal about the exact hues of colors, contrast, etc -- but the TV can undo some of that work if it's the usual low-grade consumer HDTV.