When does it make sense to go from a sole proprietor to LLC or S corp

I run a private gym studio we have double or business from last year. Currently i am just a sole proprietor. 


My gross income will be about 140k this year. My question is i am married filing jointly with 2 kids, when is there a huge tax benefit for me to change to a LLC or S corp to save more money from being taxed? Is there a certain amount of money to reach or when would it be the most optimal to save money on taxes in my situation.

 

thanks!