We almost always hand strip our terriers even when we are not showing them. When they have proper coats, this process keeps the dogs looking and feeling their best.
I usually suggest pet homes to have their dogs pulled down (stripped completely) twice a year where as our show dogs are usually groomed each week.
There are several good articles online to view how this is done and I suggest you view them to better understand how and why we do this.
If you shave or cut the dog's coat, it is unlikely that they will ever get a harsh terrier coat back.