I think a lot of it depends on the nature of your therapy and what you're working on. From what I've read here, many therapists say that they don't do therapy via email, but my therapist has done some really good therapy via email with me so maybe she is an exception to the rule. I think email or texting can go wrong really fast, so it's important to be careful about it and not fly off the handle if something isn't understood. My therapist does not always reply, but she does a good amount of the time. It's been really helpful. There are periods when I don't email at all and that's great too.