In the regular Rollei Digibase C41 kits the lifespan of part C is about one year in concentrate. The Rollei Digibase C41 manual is complete except that in case of re-use you have to wash with destilled water between the steps.
When using a Jobo rotary processor with elevator the whole process is very easy to do with a small volume of C41 chemicals. Rollei Digibase C41 is a small Fuji Hunt mini-lab C41 version from Belgium and even when doing not so many films it is a good solution for DIY C41 film development.