This morning I am breaking down a gallon of Freestyle Leagcy Pro Mic-X, into three litres of Mic-X replenisher, which will go into three one litre brown glass bottles. All my glass bottles come from Photographer's Formulary and I have many extra at this point. My present stock Mic-X is from June 2020, and in a brown one gallon bottle will last for many years. My first gallon lasted three and a half years. finally dumped it but didn't really want to. About as economical a developer as you can get at it lasts about forever and gets better as it "seasons".
Here is the stuff for XRay:
https://www.freestylephoto.biz/749710-LegacyPro-Mic-X-Film-Developer-(Makes-1-Gallon)
Kodak has great instructions to make Microdol-X Replenisher, I am listing the steps here it is easy to do.
1. Start with three quarts of 100F water
2. Add the packet of one gallon Legacy Pro Mic-X
3. Add 24 grams of photographic grade Sodium Carbonate, monohydrate
4. Mix until completely dissolved
5. Add water to bring total volume to three liters.
6. Load the replenisher into the three one litre glass bottles.
7. Starting point is 30ml per 80sq" of B&W film
That's it. This stock solution will last for years and years and years.
I have road tested this for the last ten years and it is about as cheap as you can get, since the stock solution lasts so long.
The secret to replenished Mic-X is that it is a sssslllllooooowwww acting developer. I have gone as long as thirty minutes at ambient and that's about it.