I love this quote from Sam...
The good thing about notifications is they remind your users that your app is installed. A bad thing about notifications is they remind your users that your app is installed.
Handling notifications correctly is one of the most important traits of a successful app. Users expect notifications for many different types of apps. With every user having a different expectation level, finding the right balance is very difficult. Read this post for some good tips on finding that sweet spot.
The Must-Follow Best Practices for Your Push Notifications by Sam Jarman