Hi all,
I'm starting to play with hard surface modeling, and decided to try my hand at a kilij scimitar. In order to make the blade sharp I added a few holding edges, but then when I wanted to tweak the design the holding edges got in the way. Because there are some transitions to between harder and softer edges, I manually tweaked the edge distances along the loops. But now if I want to make changes to the design itself, it seems like I would have to delete and re-add the holding edges. And for complex models I imagine this would get incredibly tedious. Are there any workflow tips for allowing for late-stage design changes, or are holding edges just going to be a point of no return?
Model for reference: 
Yeah man, you stumbled upon the pain of using subD and holding edges. As your mesh gets denser, changing something and moving loops around becomes ever more difficult, it just goes with the territory. That is why we try to leave the mesh as simple as possible as we work on it, but that's not always an option.
It's like a chef, there's a point where the ingredients are so mixed and steps have been taken that there's no turning back on the recipe. It's an apple pie as soon as you mixed the apple in there.
This is why it's mostly faster to start over than to make changes to a mesh, things get complex as you move on and moving stuff around becomes a headache. If your doing freelance and changes start to come or you're working on a studio on a production, you gain a lot of speed because it's changes over and over and over.
So once you start giving your model details, there's no turning back. You can leave iterations of your model saved up as you move along. Duplicate your model or save the file as to keep simpler versions of your mesh if you ever need to turn back to an earlier stage. Also people try to work with the Hard ops and Box Cutter workflows that make mesh editing more dynamic.