Two things to know right from the beginning: The new iPhone 16 Pro and the iPhone 16 Pro Max are the best smartphones Apple has ever built. But the more affordable iPhone 16 and 16 Plus models are also now more enticing than in previous years. Our advice: If your current iPhone is still running smoothly, the battery is getting you through the day and you’re happy with the quality of the photos and videos, there’s little reason to upgrade. And now the ‘but’. Owners of a 2021 iPhone 13, for example, might be tempted to buy a new iPhone. That’s because Apple has improved several things this year:…