MAVIC Open Pro 622 15
This bike was ridden daily 30 miles per day for years. One morning the tire was flat after sitting through the night
I replaced the tube and inflated it. The next day it was flat again
I changed the tire and inspected the rim. There are no sharp edges. There are no protrusions. The puncture is on the inside of the tube towards the tape, about midway between spokes.
The tape covers the width properly.
Inflation has been per recommendations. The deflation has happened each time about 12 to 18 hours after inflating and not while being ridden

Help
Yes, I am ordering new rim tape even though the current is in good condition. I used bare hands to feel for shards / bumps, going both directions and from different angles

The slow answer - instead of replacing stuff, patch the same tube each time. That way you have a running record of where the problems are occurring. Patches in the same place (or exactly the same distance from the valve)? Look there. If you place the inner tubes in without twist you also know whether it is a tire issue or rim issue. But even without that, knowing the inch of rim and tire where the problem is makes it far easier to find.

Also, always mount your tire with the same orientation vs the valve. Label centered at the valve is the common choice. That way, even if you take the tire off, you know where to look after seeing the tube. Hand pumps are very useful for inflating the tube and finding the hole which may be invisible when the tube is flat. Very often, the shape of the hole is a real clue to what happened.

Edit: Have you run your finger over the rm tape where the flats are happening? I"d be looking for something embedded in the tape.

Ben

When you fix a flat, you need to note where the tire aligns with the rim and tube. If you are removing the tube completely then lay it on top of the wheel and tire with them all lined up. Add a little air then find the hole in the tube. Then you'll know where to look, tire tread, sidewall or rim.

Also, you can see from one flat to the next if it's consistently in the same place. Don't rule out bad habits installing. I sometimes get a tube pinched as I try to get the bead over the rim. That sometimes takes a ride before it bursts and slowly lets air out.

In addition to the above, .rather than using your hand to find a rough spot, try using a dryer sheet-a used one is even better. They will snag on just about anything, and may find a spot your hand missed.

I appreciate the suggestion! Ordering patches now. What are your thoughts on Patches? I have never used them for more than a 1 day temp until I picked up a tube, but are they safe for regular use?

The standard to judge patches by is REMA in the green boxes. A tube of vulcanizing glue, several patches and sandpaper to rough the surface and remove mold release from the tube manufacture. There are several different sizes. Each box is complete and all you need. There are a lot of other brands (probably a few made by REMA) that are as good but not all are. Probably 90% of the bike shops out there carry REMA.

A properly glued wet patch (the process where glue is used, a la REMA) is just as good as the rest of the tube. The "glue" vulcanizes. ie forms a continuous rubber bond, the patch to the tire. Most of us stop at 3 or 4 patches but I"ve gone to at least 7 no problem.

Now the other item you may need occasionally if the repair is to get you home is a tire boot. REMA provides one but I've needed bigger and more. The time honored boot that will get almost anything home if you are inventive enough is the good ol' American dollar bill (of any denomination). But you may need more than one. I've used 5 for really big cuts in my tire. In fact, I check to see that I have 5 or more in my wallet before I leave. (This doesn't cost you anything. When you get home, just toss it/them in the laundry and they are good to spend as intended.) When you get home, search tire boots on the website. Many threads.

Ben