Need to count anything? Cars in the street, the number of chips in a package, create a counter for what you want, and count.
Need to continue later? Your counters are saved and are available in an instant.
If like me, you watch some TV show or anime, read manga irregularly, and most of the time you do not know to what episode / chapter you stopped.
Create a counter and do not waste time searching in episodes already seen.
Continue where you stopped and avoid spoil yourself.