I have a 5yo colorchecker passport, and noticed it says to replace every 2 years. I don't have one to compare it to, but are people seeing significant fading to the point where it's worth replacing?
Unless it's been baking in the sun unknown to you, I'd skip this recommendation to increase target sales
If you store it properly, it should be fine (and if it's not fine, you'll see it). X-rite suggests we all send in our Spectrophotometer's every year too, it's really only necessary for a few in specific workflows (using multiple instruments and that would be true for targets, trending data etc). Save yourself some money and use it until you notice an issue or you learned you left it sitting in full sunlight all afternoon.