The pump companies all say two days. They want to make money.
I go about four to five and am just fine.
Started having more itching lately, and after 7 years of pumping I think it's more annoying than anything.
Some folks just do really have major infections and problems and some dont.
I think two days though, is too many.
The Cozmo has a nice reminder for site changes and I think the max. it goes up to is five days.