With the limited resources available on the average MCU, and the generally fairly straightforward process loop in the applications that run on them, it is hard to make a case for using an RTOS on these MCUs. It's not until one has to do complicated resource and task management that it becomes attractive to use an RTOS in order to save development time.
The benefit of using an RTOS thus lies mostly in preventing one from having to reinvent the wheel. This is however something that has to be decided on a case-by-case basis. For most projects, having to integrate an RTOS into the development toolchain is more likely than an unrealistic idea that would add more to the workload than it would lighten it.
For projects where one is, for example, trying to balance CPU time and system resources between different communication and storage interfaces, as well as a user interface...
