I used to have a rule that if I had a replacement for piece of gear, that I must carry both the first time incase the replacement fails.
Often a piece of gear is functional because it works well in concert with our other gear and substituting one piece, you may find the hard way that your system fails because the new piece does not perform a function that the original did. Then you start to realise that you can't really "mix and match" when you pack - you must pack from a list a take THE SAME gear on every trip, or risk the results of poor plannng. Once you get a good functional pack setup you want to keep it that way so its still together the next time you need it. I just remove the sleeping bag and clothes, the rest stays packed. Its a tad heavier because you have maybe 6 bandaids because I kida ppack for the next period) instead of 2 because its not a one use pack.
I still haven't been able to hang my hammock in the backyard where I can see the stars - its because I live in a Ponderosa forest.