Answer: How often to cut it depends on the weather and how fast it is growing. In the spring you may need to cut it several times a week, in August in a dry year you might only need to cut it once or twice the whole month. The rule of thumb is to cut off no more than one third of its height at a time. It is not healthy for the lawn grass to let it get extra tall between mowings.
The ideal length depends to some extent on what kind of grass variety you are growing but if you have a typical mixed lawn the goal height would be about two to two and a half inches for your mower setting.
Here is more detailed information about growing and caring for a lawn in Wisconsin, you will need to scrol ldown the page until you get to the lawn section. (You may need to cut and paste the complete url into your browser to make it work correctly.)
I hope this helps.
Q&A Library Searching Tips