So currently I have a Samsung UN50AU8000. The model I had before this was extremely similar, from the same 'family' as far as their TV lineup goes, it was the kind that would be around 400 bucks.

Both TVs have now malfunctioned in the same way within the same time frame. The old TV I had for about two years before these thin black lines would start to appear. They weren't uniform and would sometimes go all the way across the screen, sometimes they only reach a certain point and fade back to normal. They're only about 1 or two pixel lines thick. This current TV is quickly having the same issue out of nowhere, two years after buying it.

Both TVs were also in the exact same spot in my room. To be detailed, my room is not the best insulated, nor is the rest of the house. It's old. In the summer temps can get up into the 80s indoors, and in the winter they can drop to the low 20's sometimes. This means I always have a window unit installed that runs pretty consistently in the summer, but is off during seasons when it feels nice inside and out. And in the winter I had a heater. No central AC. The thing is, the TV is adjacent to the window unit. They are side by side (not touching obviously) but are along the same wall. I'm wondering if a TV could possibly start to have issues just from being close to my unit, or being in a room where the temps can get somewhat high or low.

The TV gets used normally. It's on at night when I'm about to go to sleep, on in the morning when I wake up, yet is off at all other times, so it's not like I'm leaving it on and burning through its life cycle faster.

I should note the rest of the house is more of the same. We have another Samsung TV almost like the one I'm posting about in the living room and although it isn't having these lines pop up, it does do some weird shit every so often. Sometimes we turn it on and the whole screen is just tinted red, and we have to power cycle it a few times. Sometimes it's other things. These TVs are like boxed chocolates, we have no idea what we'll get when we turn them on. The one in my room loves to do the same kind of stuff.

We have two other TVs, non samsung, that are over five years old now and despite being lower quality in picture have never experienced these issues.

This is basically just me playing devil's advocate before assuming it's just Samsung making poor quality hardware. I'm about to purchase a new TV and won't be returning to them. And if the conditions of my room could be at play, is there anything I can do to help preserve the life span of my next model?