All of the detail on the barrel of the gun needs so many supporting edge loops. Would it not be better to use edge creasing for this or would that not work?
Good question! Edge creasing only works well if you need perfectly sharp edges - it doesn't work well for nice smoothed edges. It also doesn't work any time there's a pole near the edge, so in general I don't recommend that anyone use creases unless they have a really good reason to.
I'd add that creasing edges can be useful early on your project to actually avoid adding support edges too early and get a mess later if you need to make some changes: getting from C to D requires only to lower one vertex, whereas switching from A to B will need more adjustment.
This answer is a bit late but wouldn't an edge's Bevel Weight and the Bevel Modifier take care of that? Those let you keep the mesh simple and add some dense edge loops procedurally. I used that for the robo-orb retopology.
dustincompetent you sort of could, but you wouldn't have a lot of control:
As opposed to holding edges:
spikeyxxx I see what you mean and I wouldn't replace every complex bevel with the weights setting. But for simple cases like in the original question, they do come in handy.
By the way, Bevel Weights do get a lot more control over the width, if you set the Width Type to Percent:
dustincompetent you're absolutely right, it should be set to Percent! Thanks for pointing that out.
I only learned about that yesterday from Gleb Alexandrov: https://www.creativeshrimp.com/variable-radius-bevel.html