I make the vacuum seal bags extra big for my hops. When I cut them open to take out what I need for a recipe there's still enough clean bag material left over to reseal the bag. It just gets about an inch shorter whenever I brew.
I also buy DME in bulk, when I get a new bag, I split it into vacuum-sealed bags pre-measured for a 1l yeast starter. Not quite as convenient as the Perfect Pitch stuff, but pretty near, and much longer shelf life.