[ruslan_mart]

Сорян, торопился и опечатался. Работает:

function getRandomInt(min, max) {
  return Math.floor(Math.random() * (max - min) + min);
}

const blockList = Array.from(document.querySelectorAll('.fact_block'));
const limitationBlock = document.querySelector('.limitation');

const INTERVAL = 1000 * 60 *  60 * 10; // 10 часов
const STORAGE_KEY = 'random-block';

const currentStorageValue = Number(window.localStorage.getItem(STORAGE_KEY));

if (blockList.length > 0 && ((Number.isNaN(currentStorageValue) || currentStorageValue < Date.now() - INTERVAL))) {
  const randomBlockItem = blockList[getRandomInt(0, blockList.length - 1)];
  
  window.localStorage.setItem(STORAGE_KEY, String(Date.now()));
  
  randomBlockItem.classList.add('show');
} else {
  limitationBlock.classList.add('show');
}

<div>
  <div class="fact_block">1</div>
  <div class="fact_block">2</div>
  <div class="fact_block">3</div>
  <div class="fact_block">4</div>
  <div class="fact_block">5</div>
</div>

<div class="limitation">limitation</div>

.fact_block, .limitation {
  display: none;
}

.fact_block.show, .limitation.show {
  display: block;
}