In 2026, the decision to keep data roaming turned on depends entirely on your specific mobile plan, but for most people, the answer is no unless you have a confirmed international package. If you leave roaming on without a plan, "background data" (like app updates and email syncing) can result in "bill shock" with charges reaching hundreds of dollars in a single day. However, if you have a carrier like T-Mobile (U.S.) or a "Roam Like Home" plan from a European provider, keeping it on is perfectly safe and convenient. A high-value "pro" strategy in 2026 is to disable roaming and instead use a Travel eSIM (like Airalo or Jetpac), which provides local data at a fraction of the cost of your home carrier's roaming rates. If you do keep it on, ensure you "Toggle Off" automatic app updates and high-data social media settings. In an emergency, having roaming "available" (but toggled off) is wise so you can quickly turn it on for navigation or a critical call, but for the rest of your trip, rely on Wi-Fi or a local SIM to save your budget.