How often is necessary to change colostomy wafer?

Hi,

I had total colectomy and ileostomy five weeks ago and even though I do have some help from my ostomy nurse, I’m now left alone to take care of my stoma bag and I immediately ran into one simple question – how often should I change the wafer? I’ve been changing the bag every three days and when I changed it last time I noticed skin underneath the wafer is reddish, so I’m wondering if I’m changing the wafer too rarely, or am I doing something else wrong? I do first put the protective powder, then the wafer then the pouch, but like I said, the skin underneath the wafer is red and maybe I’m supposed to change it more often?

thanks, Lily