Every dollar you have coming in, you invest. You may invest it in food or shelter, you may invest it in a material item or experience that makes you happy, or you may invest it in the stock market. Be sure that you understand where you're investing your money and that the investment's return, whether in happiness or dollars, is worth it to you.
You don't need an excuse to break the rules because there are no rules. If you have everything you need and want to get to FI faster, save it. If you're willing to move FI incrementally farther away to get whatever splurge item you're thinking about, go for it. If you're thinking about the journey to FI as strict adherence to rules, you'll likely cheat occasionally. If you think about it as making decisions that maximize your happiness with an accurate understanding of short-term and long-term returns, you'll be more likely to make wise decisions and the worst case is that you'll find you made a sub-optimal decision. If that happens, learn from it and make a better decision next time.