A feature requst:

(edit: A - absolute limit)
A settable limit, which when is reached, will play a sound (configurable audio file) and/or vibrate the phone (silently).
A toggle on there also, whether to stop counting after the limit, or continue counting. If stop was wanted, vibrate or play the sound again when touched, so the user really notices (s)he has reached the limit.

One use case for this 1up is that you do not want to look at the screen when counting something, but when the limit is reached, you would want to know.

(edit: B - periodic limit)
Also to develop that futher: a settable periodic alarm. Say, play a sound or vibrate for every 12 counts. (12, 24, 36, 48, ...)

Edit: actually, both can be combined, so there is either absolute limit (A) or periodic limit (B). Absolute limit won't continue counting after a limit but alarm again and again if tried, but periodic limit will allow to calculate futher and alarms again when next time the limit is reached.