Clipping a budgie’s wings makes taming easier, and also makes it a bit safer to have your budgie out of the cage. A budgie who hasn’t had experience flying can hurt themselves by flying into windows and mirrors. Also, there’s the risk of a budgie flying out a window or door unexpectedly opened or accidentally left open. Clipping a budgie’s wings is not particularly detrimental to them, as long as the clip is done properly so that the budgie can slow his descent to the ground but is not able to get lift. The main drawbacks are that the budgie won’t be able to learn the skills of flying and won’t be able to get as much exercise.
Leaving a budgie unclipped can be rewarding. A tame flighted budgie, once he learns how to fly well, can experience a sense of independence by being able to fly where he wants to go. When he’s hungry, he can go back to his cage to eat. When he’s lonely he can fly to you to hang out. When he wants to visit with someone else he can go see them. A flighted budgie will also be able to get more exercise. The extra freedom and independence a bird has can show up in their personality, which usually makes them more fun and interesting birds. With a flighted bird in the house, everyone should be aware of the risks and should be particularly careful when the budgie is out, especially to close all windows and doors, not turn on ceiling fans, and keep the budgie away from the kitchen when cooking. Everyone needs to know when the budgie is out of the cage so that they can practice these common sense safety measures.
Remember, if you want to make taming easier but want your budgie to be flighted later, you can always do a light trim for now to ease the taming process, and allow the flight feathers to grow out with the next molt if you decide to keep him flighted. As the flights slowly grow back in, it will give him some time to learn the skills of flying until he is fully flighted.