Do Combos go bad?

I've been hearing a lot about the benefits of using cryptocurrency combos for transactions, but I'm curious about the potential downsides. Specifically, I'm wondering if combos can ever go bad or expire? I've seen some people suggesting that they should be refreshed or updated periodically, but I'm not entirely sure why. Can you explain the potential risks of using outdated or expired combos, and any steps I should take to ensure that mine remain secure and effective?