What account to keep true expenses in?

Okay, so I’ve got about $460 sitting in my checking account because it’s money I’m saving for my True Expenses™️ (or what I call my Ticking Time Bombs 🧨). So my question is, where do you put this money you’re serving? In your checking account or savings account? Would it be better to periodically transfer this money to my high-yield savings account so I can be earning more interest on it? It is that just overly complicated and make it to difficult to use when I need it?

Thanks! Let me know your thoughts!