Yeah, I remember going 5-7 days when I was first pumping… it just didn’t seem like I needed to change sets sooner. Boy do I feel stupid now 
Currently, 3 days is pushing it for me… I do notice the absorption issues after 2 days. I can’t use Humalog or Novolog due to extreme site irritation, and while I don’t seem to have the same physical reaction to Apidra (thank goodness!), it seems like my sites are more prone to not working quite as well after 48 hours. I don’t know if it’s due to the change in insulin or just changes in my body, but it is what it is.
Oddly enough, the only sets I’ve been able to push to 4 days have been steel ones… and those are supposed to be used for less time than the others… but I haven’t had any issues with clogs and the absorption seems to be the most stable with those. I don’t think I have a teflon allergy, but it does make me wonder about how differently my body adapts to teflon vs steel.
However, I do have to say that the way the sites heal when they’re only in 48 hours is amazing… after a day it’s almost like nothing was there, especially with steel sets. The only ones you can spot longer any any that happened to bruise. When I was leaving sets in much longer, I had many “healing” sites at a time… I rarely have any now.