Q:

Is it a bad practice to use stateful components bypassing redux?

Say, I don't want to keep my checkboxes state in global redux store. Cause I don't want to deal with actions and reducers for this small local state. So I want to explicitly use setState() inside my component.
Is it a bad practice (for instance, in testing aspect)?

A:

Per the Redux FAQ entry on component state vs Redux state:

Using local component state is fine. As a developer, it is your job to determine what kinds of state make up your application, and where each piece of state should live. Find a balance that works for you, and go with it.
Some common rules of thumb for determing what kind of data should be put into Redux:

Do other parts of the application care about this data?
Do you need to be able to create further derived data based on this original data?
Is the same data being used to drive multiple components?
Is there value to you in being able to restore this state to a given point in time (ie, time travel debugging)?
Do you want to cache the data (ie, use what's in state if it's already there instead of re-requesting it)?

A:

It's absolutely fine to keep the checkbox state in you local state as long as it doesn't depend on the data.
A good practise is to keep all you data in your redux store and the ui-related state in you local store.

