I want to start emailing coupons to customers to increase sales from Monday through Wednesday. I tried it once - emailed a coupon for 25% of the entire order on Wednesday only. The response was pretty good. I sent it out twice - in the morning and right before the rush hour. The question is, how often should I do this? One thing I don't want to do is inundate my customers with constant emails. Any recommendations would be greatly appreciated. Thank you in advance!