In 2026:
I used to bring a laptop in case I needed to manage some home finances or admin while out of the country. Now most of it can be done on the phone.
For those worried about the phone being stolen and hacked, there are multiple levels of security you can use.
First, security of the phone itself. If you aren’t already using a passcode or biometrics to lock your phone, you need to be. Because your phone can be stolen in your home city too. I also set a short idle period before the screen locks, like 1 minute, so that if the phone is lost or stolen, a thief only has 1 minute to start hacking before the phone locks itself. (An effective thief knows that if they manage to swipe your phone on the street while you've been using it unlocked, they need to start hacking that phone ASAP before it auto-locks on them.)
Second, security of each company's account on the phone, like banks and utilities. If you manage them through a web browser, don't stay signed into any of those websites, sign out and close their tabs, and only sign in when needed. This way, if the phone is stolen and also hacked, when they open the web browser, your accounts are not already open and vulnerable, they'll have to figure out the login info for each one (unlikely).
Third, if instead you manage them through apps, like a banking app, understand that in addition to your username and password for the bank, see if your phone lets you turn on a security step to get a particular app open, like entering the phone password or passing Face ID. Apple iOS lets you add this requirement to any app you use. So that’s two different levels of security that a hacker would have to get through to access that account.
30 years ago (for those saying "no digital!") :
Before everything went digital, we would cover bills with the help of trusted friends/family. When as a young person I was away for a long Europe trip (with Europe Through the Back Door in my backpack), one of my housemates was my best friend, so I entrusted them with a short stack of signed blank checks and a list of upcoming bills and said "Watch for these bills in the mail, and when they come in, pay them." You can do the same with a trusted family member.
First, move to Texas to avoid tge state income tax.
Rick Steves' home state of Washington also has no income tax, and is a bit greener with fewer climate extremes... :)