Almost all the apps I installed on my phones are must-have apps. This conclusion was based on a thing happened yesterday. Yesterday, when I watched a picture taken in 2009, I was so excited about seeing my old friend again. Unfortunately, the picture was not very clean, especially my friend's face. In that case, I immediately remember an app on my phone. That is an AI tool which can help me fix old picture. It didn't take me much time, then a clean picture appeared and all the details were perfect. Even pictures can be made into a short video by this app, and people in the pictures can smile and move. Maybe this app I just use once in a year, but it's a must-have app because I must use it sooner or later. This thing reminds me of some other things happened many year ago. At that time, I usually used a software called PS to fix pictures that often costed me many hours to finish a project. So, I am sure that more and more apps will be downloaded on my phone. Each of them is a must-have app!