Don't Install iOS 10.3.3 Beta If You Only Have One Device
There are also some reasons to avoid the iOS 10.3.3 beta today or, perhaps, altogether.
If you only own one iPhone or iPad, you should avoid the early version of iOS 10.3.3. This is early software and early software might conflict with your apps and services and it could have a negative impact on your device's performance.
If you only own one device and you rely on that device for work, school and whatever else you've got going on in life, we'd skip the beta. Apple agrees with us.
In its Beta FAQ the company "strongly" recommends installing iOS beta software on secondary devices rather than primary ones.
You can downgrade from the iOS 10.3.3 beta but only to iOS 10.3.2. You can't downgrade to anything older than that.
So, if you're currently on iOS 7, iOS 8, iOS 9, or an older version of iOS 10, and you don't feel the need to try iOS 10.3.3 ahead of its official release, you probably should wait for the final release.