Calvin, it is recommended that you flush until you have no more stones - every 2-3 weeks and then flush a couple/few times a year for maintenance.
I've made flushing a part of my life. I'm still working on changing my diet and lifestyle for better health. There are so many opinions out there it's hard to decide what is right for me. I'm getting there slowly but surely!
Epsom Salts give me a little headache too... Maybe I'll try a differnt method sometime but I'm happy with Hulda Clark 's for now ;)