Burn-in is a misnomer.

OLEDs don't burn their image into anything. CRTs used to burn in right onto the screen making it impossible to fix without physically changing the "glass" (really the phosphor screen).

What happens is the OLED burns out unevenly, causing some areas to be weaker than others. That clearly shows when you try to show all the colors (white) because some areas can no longer get as bright as their neighboring areas. It is reminiscent of CRT burn-in. LCDs just have one big backlight (or multiple if they have zones) so unevenness from burnout in LCDs is rarely seen, though still a thing.

So, OLED manufacturers do things to avoid areas from burning out from staying on for too long like pixel shifting, reducing refresh rate, or dimming areas that don't change for a long time (like logos).

There is a secondary issue that looks like burn-in which is the panel's ability to detect how long a pixel has been lit. If it can't detect properly, then it will not give an even image. This is corrected every once in a while with "compensation cycles" but some panels are notorious for not doing them (Samsung), but once you do, it removes most commonly seen "burn-in".

You'd have to really, really leave the same image on your screen for months for it to have any noticeable in real world usage, at least with modern OLED TVs. You would normally worry more about the panel dimming too much over a long period of time, but I don't believe lifetime is any worse than standard LCD.

TL;DR: Watch RTings explain it