This is a concept I learned a long time ago. Long enough that I don't remember where I learned it, only that I picked it up out of a magazine.
There are three stages of learning for any child. First is the absolutely new, next is the reminder and third is actual knowledge/understanding.
When something is absolutely new, there's a certain shock factor to it. Just absorbing the information takes effort. At this stage, the child shouldn't be expected to perform the task or behaviour. Just getting them to repeat the information back to you is a positive step.
The next step is the reminder stage. The child knows what is expected but can't quite make it without some prompting. This is where warnings of potential consquences are appropriate.
The final step is actual knowledge/understanding. The child knows how to do the task or how to behave in a situation without any outside help. Immediate punishment can now be implemented for failure to comply.
The example given was a child brushing their teeth. At two, just the concept of sticking the brush in their mouths might be overwhelming. At five, they might be able to do it themselves with adult supervision. At fifteen, if they don't brush their teeth, they can lose privileges.
This is one of the few parenting techniques which I find translates for children with autism, albeit with some tweakings. Our children are likely to spend much longer in the absolutely new and reminder stages for any particular task or behaviour expectation. And we're likely to have to break down the introduction of the task into smaller tasks.
I find it helps to remind me to be patient with them. I can tell myself that they're still in the reminder stage without completely losing hope of them one day reaching the understanding phase.