This is a problem that I've struggled with during the past year. As of the last six months it seems that I've solved it.
This time last year I was experiencing absorption anomalies including third day infusion site highs. That led me to try the Omnipod. I reasoned that it would allow me to easily try alternate delivery sites.
After 28 years of using various pumps, I was also curious about how well the Omnipod would work for me. I experienced limited episodes of pod change highs and finally figured out how to take a bolus just to bridge the gap in control. The pods worked reasonably well for a time and I toughed out any absorption glitches so I could give the Omnipod a reasonable trial.
Five months in I decided to drop the pod as I was having regular intermittent hyperglycemia due to pod occlusions and poor absorption. I went back to my old Animas Ping pump and experimented with some different infusion sets. I had been a long time user of the Inset-30s. I got some sample Contact-Detach (steel cannulas, 6mm and 8mm depths) and Insets (90 degree insertion and also 6mm and 8mm).
I talked with an Animas sales manager at that time. He is also a T1D. In addition to trialing the infusion sets, he told me that he had had some success restoring his tired abdomen sites using a loofa sponge when showering.
I experimented with the various infusion sets and using the loofa. I settled on the Inset 6mm and am still successfully using it to this day. I can't say for certain what exactly caused my absorption problem but it is indeed fixed. I'm thinking that the infusion set change along with using the loofa sponge restored the viability of my infusion sites. My last A1c came in at 5.9%.