depends where you are traveling from and when. If you can book far enough in advance it's usually cheaper.
Best advice I'd give though is to look at your journey and note down the trains involved and cost, then look at booking the individual legs of the journey and see if there's a price difference. You could pay a lot less and still be on the same trains you would be on with 1 single journey ticket.
e.g. I just did a random search from my town to St. Bees on June 20th, it comes up as £74.50 changing train twice but I split the journeys into 3 separate tickets on the exact same trains and the total came to £38.90, saving £35.70 (if I can count).
Hope that makes sense?