Maybe you’d prefer all your bills to come out on payday, so you know what’s left in your account is yours to spend, or, if you get paid weekly, you might be best spreading payments out across the month so you aren’t left short? For some bills, you can even look into paying annually. It means a larger chunk leaving your bank account in one go, but then you don’t have to calculate regular payments into your budget and for some things, like car insurance, a one-off payment may mean you pay less overall.
If you want to change when you pay, it usually just involves a call to whoever you are paying the bill to.