I don't take a puffy year round on the trail. I typically don't start taking it again on trips until mid to late October but I was watching red beards Long Trail hike thru Vermont which started June 1st nobo and they seemed to be wearing their puffys an awful lot. I will be walking Goose Pond MA, to Hanover starting Sept 1st, and wandering if I will need it that soon in the season? Red Beard was saying while he was hiking it was in the 40's some mornings, When I walked from Salisbury, CT sobo 240 miles last October, I sent my puffy, beanie and gloves/ leggings home after 5-6 days because they were never being used.
I also figured I would bring my megalight sleeping bag which is what I use all summer, but if I need a puffy I am wondering if I need my 15* only due to I sleep pretty cold. I am comfortable in my 30* bag all summer but am never too hot when I don't zip it up.