Hi,
I purchased the Hefty One Zip bags (2.5 gallon, I believe) to put each of my kids' outfits in for each day. When I rolled them and got all the air out everything looked fine but then the next morning some of the air had come back in and the "vacuum effect" was gone. I'm disappointed but it seems they do not seal completely. I was going to go buy the regular ziplocs but I think I'm just going to skip the bags and pack the old-fashioned way! I've already busted my budget buying all the other things my Type-A Disney Obsessed brain thought was necessary. I'll still use the bags I bought to keep things organized, though. Good Luck!