How much is too much?
The ACT is not a one and done test.
For most students it takes three, four, or five times to maximize a score. It’s just like sports.
A basketball team does not practice all season for one game. They usually have a non-conference portion, then the conference games, and then the season ends with the state tournament.
The early games allow the team to work out the kinks, so they can be ready by the end of the season. The ACT should be approached the same way.
I do think it helps to start early, which is why I recommend students take their first ACT either in April or June of their sophomore year.
However, I’ve had students do the February ACT, State SAT in April, and then the June ACT and they did fantastic!
A lot of college-bound students will take the ACT three, four, or five times to maximize their scholarship offers. The key is to have a plan that is realistic, and make sure it incorporates the June ACT test.