Anyone doing it? Seems a bit sacrilegious to ask.. Currently tubeless but I don’t like the tubeless maintenance (topping up each spring, clogged valves, etc) so debating going back to tubes next season.
I ride mostly flowy single track, nothing too technically or rocky. Never had a flat around here.
I have a TPU tube in my under saddle bag. I’ve had to use it once when first started tubeless and spaced that I had dyna plugs. easy in, and held up for the race. Just have to make sure you get the right size as they aren’t as stretchy as butyl or latex
Don’t use cheap ones. They are thinner and weigh less sure but my experience with cheap ones from Amazon has been poor. 3 of 3 have had problems. They lose air as fast or faster than tubeless, had one leak at the valve stem, another where the tube ends are joined and two with pin holes so small they are virtually undetectable. They would lose 15psi overnight when installed at “full” pressure but just inflate enough to fill it without stretching and it would hold air forever. I had to overinflate them at risk of damaging them just to find them submersed in water.
TL;DR - they are light, make great spares in a a saddle bag, cheap ones aren’t worth it.
Based on the description of your riding, why not good ol’ butyl tubes? How would TPU be of benefit to you over butyl?
Lighter, easier to pack a spare, less rolling resistance.. Seems to be a lot of benefits?
Totally true, but IMO, those are small and inconsequential for non-competitive riding. Personally, I run tubeless and carry a light butyl tube, just in case the sealant or a plug doesn’t work. 3-4 oz of sealant and stems weigh ~90-120gm. The spare 29” butyl tube is 160gm.
+1 on butyl tubes if you don’t want to run tubeless. And you might not have had any flats running tubeless, but keep in mind that the most common punctures are so small that we are never aware that they happened (they seal with any obvious signs). There are lots of places I ride that I never have flats, but I know I would with tubes. Not saying that’s the case for you, just pointing it out. And if there is no risk of flats where you ride, you might just consider running tubeless without any sealant (just don’t top off next spring). In my experience, most tubeless tires hold air fine once they are initially sealed (long after the sealant dries out). Lighter than tubes, just no puncture protection.
I’d just add reserve high flow valve stems. Should reduce clogs I have them on 3 wheel sets and never clogged (granted, one set is new).
For adding sealant, I take a tire lever, break a seal in one spot, and use park tool sealant injector to just put the nozzle in the small gap and add sealant. Takes all but a couple minutes.
if I want to measure the sealant, I use the same tool to just suck the sealant out, shows how many oz on the tool, then add accordingly. I know this doesn’t answer your question, but just a thought.
All fair. But it’s still more hassle than not dealing with sealant at all 
I tried to top sealant up through the stem this year (removed valve and used a piece of clear piping). Total fail..
One flat is more work than topping up sealant for an entire year. This is one of those scenarios where I’d be surprised if you didn’t regret the decision…
Agree on the Reserve Fillmore Valves - love them so far.
Benefit of tubeless