I rarely wash my quilts - they have to desperately need it - I shake them out and vacuum them and then put them away.
Most quilts do not need washing - most espcieally if they are just used for show.

I quit using fabric softner sheets quite a few years ago for anything, other than if you want to keep mice out of something. #1 I personally find the smell "not good" gives me instant headaches(miagranes) #2 One day my son "caught" a mouse and at the time was doing a project so was going to keep him for the project alive (a living diarama(sp)). He wanted to give him something so use as a nest and gave him dryer lint(which was from a dryer that uses dryer sheets.) (We completely forgot that mice do not like dryer sheets.) Well, my son put the lint in with the mouse, not realizing what was going on the mouse started freaking out but we did not put two and two together, He died within 2 hours. Since then I guess I just have a hard time using it. If it does that to a mouse that quickly I do not care to use.
I would be concerned about the chemical and what it would do over time too.

Fabric softener has oils in it and leaves a residue. Not good for any clothes. Fabric sheets are not really good either but I put two in and dry for 10 minutes take the quilt out and lay it over chairs to dry. It will have just enough softness. I roll my quilts that are being stored and do not use any type of softener and only the mildest soap.

For those who pre-wash fabrics before cutting, etc. that is fine [it is my primary choice].
However, be aware that fusible[s], or Peltex/Timtex will not adhere properly to your textile that has been dried with any type of fabric softener.
I had that difficulty, experience is a great teacher.

I don't use fabric softener. I don't want to add chemicals to the fabric or make it look dingy.

I put vinegar in every load of washing. I put it in the fabric softner holder. It will take out residue and your whites will look great after a bit. Also softens. i use about a half a cup. Much Cheaper than fabric softner. Try it you'll like it.

I use vinegar also. Works great

I don't use fabric softener when I pre-wash my fabric, but when the quilt is finished, I don't see a problem with it.

I do and always have. And I have old quilts from years ago. They are still just fine.

Great answer!