Now you know when to use Flowables, take a look at the conditions where you should prefer Observables:

• When you are dealing with a smaller amount of data (less than 10,000 emissions)
• When you are performing strictly synchronous operations or operations with limited concurrency
• When you are emitting UI events (while working with Android, JavaFX, or Swing)

Also, keep in mind that Flowables are slower in comparison to Observables.