I’ve never needed Skin Tac or any other helpers. Even when I’ve been active and sweaty in hot, humid weather, or spending a lot of time in water, the pod sticks. I do use it for my sensors, but I can get four weeks out of those easily, so I want them to stick long and hard. I guess I could use Skin Tac with a pod and then wear a dead pod for four weeks just to prove some kind of point …
I will also say, do not be nervous about trying new places. It took me a while to move beyond my default abdomen/belly. I wasn’t convinced pods would be comfortable in areas without a lot of flab subcutaneous tissue, but surprisingly they were. Arms, round the back, upper butt – all have left me wondering why I didn’t try earlier. The only exception was the ribcage, one of @Eric’s ideas that I suspect only works in Eric Land.