Timing of the popup displayed by requestReview.

The Behavior of that method is when it gets called in your app such as the end of a game level or something similar, it will pop up and ask if the user is enjoying this app. The user can rate it and leave a review or they can choose not to. It really doesn't matter how many times it gets called its up to Apples algorithms to decide when to show it, so it doesnt annoy the user it will only popup for a single customer three times a year. In developement mode it will pop up everytime it gets called, but not when in the app store. Apple just doesnt want us to hooked it up to a button that says "Rate this app" because sometimes it wont popup. Just call it when your users have a feel for your app so they can decide if they like it or not, calling it when the app launches probably a bad idea because the user knows very little about your app. I call it when user dies a couple of times and taps the play again button. Every app is different just call it when it makes sense to get the best ratings. As for the timing pretty much instantly when the method gets called, just like any other method. In my apps and games it gets called way more then 5 times a day per user, you dont have to do any special algorithms, Apple did that for us its litterally an amazing feature.

Good Luck i hope this answered your question.