Gathering information to follow up on a beginners video.
How often do you change your backing out? I think some of my reels are holding 20-year-old backing! It is feeling kind of "fuzzy" now, even though I NEVER see it.

What kind of "gadget" do you use to change out your fly lines? It seems like there are not to many of those that are SIMPLE or economical?
I did find this 3D printer file that looks like a bench bound line changer ...

https://makerworld.com/en/models/431743-fly-line-winder-spooler#profileId-336310

and it looks good for a single purpose. But there has to be something someone makes somewhere (we hope USA) - that does it all?

Have you looked at the Scientific Anglers' Regulator Spool? I don't have one, but I've thought about getting one several times. I just use my line dryer, an old 16" cable spool with dowels mounted around the perimeter, set on a conduit axle. Works great, but it's always in the way when I'm not using it. Something I've used in the past is an old bulk line spool mounted on a drill if I need to strip a whole lot of line.

Every so often, I get empty line spools from Tackle Town to use when changing lines out. I usually just spin them on a steel rod with a wooden dowel. If I did more, I would rig up a drill like Jim suggested. I don't change lines very often, though. IslandJim

I use Dacron or Powerpro backing. I go into my backing all of the time. Both will last a really long time unless you drag the backing across rocks or other obstacles. I have backing that has been on my reels for a decade. When I change it I just pull it off by hand while I watch TV. I roll the fly line on the reel with the tip of the line on the reel and fill the reel with backing. I then walk through the house and pull out the line on the floor. Finally, I tie the backing to the spool and reel it back on the reel. That way I get a full spool of fly line and backing. A big wahoo or tuna uses a lot of backing.

Found this thing, apparently made in S. Africa?
https://www.madriveroutfitters.com/p-16890-omnispool-switchbox-kit.aspx

Have one of these coming to me from the USA distributor. Apparently the Omnispool originates in South Africa.

Also had the 3D print made of that bench-style liner. Really two different purposes for these two things. Hats off to the creative minds behind both for sure!!

Perhaps more important than changing out the backing is inspecting the knot from your fly line to your backing. I've had to cutoff a few inches and re-tie several times due to wear and tear on the knot as it was pulled through the rod eyes, or as the fly line cover gets worn out. A good UV glue really helps protect that, but you have to make sure it is nice and smooth so that it doesn't hang up as it gets pulled out.

As far as gadgets, the Piscifun line spooler from amazon works pretty well. I always keep the mfg spool from new lines for storage and changeouts.

Hey Mr. Ford! Missed seeing your response! I have this real old gadget that I use and it winds off a fresh line really well, but it doesn't wind ONTO the empty line spool well at all. I did get my 3D printed version from my printer yesterday, and it looks like a puzzle to put together, albeit a simple puzzle! Bearings come in today - skateboard wheel bearings.