How should we use async await? [duplicate]

Answer 1

Both options are legit and each option has own scenarios where it is more effective then another.

Of course always use await when you want to handle result of the asynchronous method or handle possible exception in current method

public async Task Execute()
{
    try
    {
        await RunAsync();
    }
    catch (Exception ex)
    {
        // Handle thrown exception
    }
}

If you don't use result of asynchronous method in current method - return the Task. This approach will delay state machine creation to the caller or where ever final task will be awaited. As pointed in the comments can make execution little bit more effective.

But there are scenarios where you must await for the task, even you do nothing with result and don't want handle possible exceptions

public Task GetEntity(int id)
{
    using (var context = _contextFactory.Create())
    {
        return context.Entities.FindAsync(id);
    }
}

In the scenario above, FindAsync can return not completed task and this task will be returned straight away to the caller and dispose context object created within using statement.
Later when caller will "await" for the task exception will be thrown because it will try to use already disposed object(context).

public async Task GetEntity(int id)
{
    using (var context = _contextFactory.Create())
    {
        return await context.Entities.FindAsync(id);
    }
}

And traditionally answers about Async Await must include link to Stephen Cleary's blog
Eliding Async and Await