I REPLACE my current outfit with the old outfit. Then open my Nude base avatar. Of course none of the new stuff, i.e., Slink body, is worn. I can easy see what I need to update and wear or add those things. Once I have the outfit updated I can select SAVE instead of the default Save As… I usually rename the outfit changing the year, ACI, and whether it is classic, mesh, or Slink.
The update goes quickly.
I have stuff I bought in 2008… well I was much more into free stuff then… that is still floating around in inventory. About 2014 I began to realize I needed some way to get OLD stuff out of inventory. Now I have a folder for SHOES. It used to have CFM’s, Spikes, boots, favs, and just a chaotic mess. Now I have SHOES->[2014, 2015, 2016]->[Slink, Classic]->[shoe name].
I do something similar with dresses, tops, latex, etc. Most of my folders now have a YEAR folder.
I am not obsessive about keeping 2014 stuff in the 2014 folder. If it is a favorite and I wear it often, I may move it to the 2016 folder. But, I mostly leave it in the folder of the year I got it.
This is making it much easier and faster for me to go through and clean things out.