The day I change the infusion set is my Day 1 (like you say above - change on Tues - comes out on Thurs) - that’s how I remember. Also - I have found if I put enough insulin in my insulin reservoir for just 3 days (usually I’m down to about 6 units when it’s time to change) then I can’t go any longer.
I used to originally fill the reservoir up with 200 units (I didn’t know any better as I was self taught with using pump), but then of course, I’d go for 4-5 days (I think one time it was 6 - ugh). Then I was told by a long time pumper once I joined up to online forums (thank heaven for these places), not to do this, as scarring/infection can occur, which in the long run, will eventually cause absorption probs.
I’ve been pumping over 2 years now, and so far, with rotation of 1", doing okay (I use stomach, back area (around the love handle areas above below waistline), and my legs).