My longest streak of consecutive days diapered is 8 days. This happened on two occasions, both after I had finished school for the year, I had a few weeks off before my contracts started and I used them to my advantage, diaper up and unwind. Going 8 days in a row was really fun, I wasn't in baby mode all the time, but still, I was most certainly a comfy diaper boy for that time.
My longest streak in baby mode was 3 days straight. I think I was able to immerse myself in baby mode and stay there for those 3 days because I had my Mommy friend with me. I spent a long weekend at her house and I was a baby from morning until night, Friday evening to Monday morning, it was very very fun. You'd think one would get bored being a baby for that stretch of time, but Mommy had a full weekend of fun things planned so I was always stimulated and entertained
In all honesty, wearing for a week in my experience isn't too different from wearing for a few days in a row, you go through more diapers, but that's about it. It's just as fun and convenient as any other time you're diapered
I would say that if you are going to be diapered for any elongated stretch of time, you are going to want to make sure you have enough diapers to keep you covered. If you run out of diapers the streak is over.