(first rough draft)
When you are reupholstering furniture with a trim between the fabric and the wood, What type of trim should you use. This article will give the pros and cons of each type of trim.

Gimp Trim

When I worked with my dad years ago we stocked many colors of gimp. In that case, it was always there ready to go.

Nowadays, for me, a 36 yard card of gimp cost $15 wholesale, plus shipping. I'm not sure how many colors of gimp are available nowadays, but I have an old gimp chart that has 99 colors. Even it there were only half that many colors nowadays, that still $15 X 50 colors = $750. I'm not going to spend that much just to stock gimp. My other choice is to either order in a roll of gimp each time I need 2 yards of gimp, or go take my time to run across town to a fabric store to get a couple yards of gimp. If a client wants gimp, I send them to the fabric store to buy it.

Double Welt

One reason I also like double welt is that it always matches.

Then, most of the people I give double welt as an option, choose double welt. So, while I still use gimp occasionally, most of the time I use double welt. Besides the customer liking it, it is a lot simpler for me to make up the double welt that it is to run across
town, not finding a good match, or having order it in. So, this is where I have a different viewpoint Bern, at least in my situation. Making a few feet or a few yards of double welt is easier and less expensive than the options.

Using Trim or Not.

Should you use trim on the backs of cornice, double welt, or no trim

I make quite a few new cornices

and use gimp fairly regularly, when needed, on the back of them.
Sometimes I finish the back of the cornices off with gimp, like this:

And sometimes I finish the back off without gimp, like this:

Double welt and gimp both have their places. One is not better than the other. They are just different.