I regularly need to count how often certain events or actions occur throughout the day. There are a number of counter apps for Android on the Google Play Store, but for my money Advanced Tally Counter is the best one available.
As can be seen in the screenshot below, like most counter apps the free version of the app allows you to set up multiple counters to track any number of user-definable things.
Where Advanced Tally Counter differentiates itself is in its additional features that do, however, come at a cost of $1.99.
There are a lot of features in this app, but the ones I needed were timestamps on increments/decrements, and the ability to export and share the counter data as a CSV file.
Well worth the $1.99 cost.