Don't Install If You're Worried About Problems
If you're having an excellent experience on iOS 11, iOS 12.0, iOS 12.0.1, iOS 12.1, iOS 12.1.1, iOS 12.1.2, iOS 12.1.3, iOS 12.1.4, iOS 12.2, iOS 12.3, iOS 12.3.1, iOS 12.3.2, iOS 12.4, iOS 12.4.1, or iOS 12.4.2, and you're not interested in iOS 12.4.3's changes and/or you're nervous about it potentially damaging your device's performance, you might want to hold out for a few days.
The iOS 12.4.3 update brings security patches and improvements to two-factor authentication, but the update's also brought its own set of issues to iPhone, iPad, and iPod touch.
The current list of iOS 12 problems includes abnormal battery drain, issues with first and third-party applications, broken Bluetooth, problems with Wi-Fi and cellular data, installation issues, lag, random reboots, issues with Face ID and Touch ID, and problems with 3D Touch.
If these initial issues concern you, you might want to hang around on your current version for a little while longer.