Video standards are continuing to change rapidly, with the recent rise of 4K and HDR already beginning to give way to 8K and beyond. Plus, refresh rates for games consoles are also beginning to go beyond the standard 60Hz, which requires yet more data to be transferred per second. If you’re still using the HDMI cable that came with the TV you bought eight years ago, it might not work at all with a 4K video source like an Xbox Series X or an Ultra-HD Blu-ray player, and if it does work, it might introduce errors in the picture. The same is true (more so) for HDR. Luckily, this is easy to test - just connect everything up with your cable and check if your TV gets a signal, recognises it as 4K and/or HDR, and displays it without any obvious problems. If it does, you’re good to go. If not, you’ll have to buy a new one.