Thorp

Hey, I could use some advice. Me and a friend have made pures again because the wild has returned. He's a pure strength build and I'm a ranged/2her. He's almost 90 str and I'm around 82 ranged and strength. We're around level 60cb. So my question is, at what levels is it worth it to start getting prayer? I don't mind prayer switching if the damage really is that much better. Should we both get 31? Or should I stay at 1 or get 44? We've always sort of had the idea that it's garbage in F2P but we've never made it this high on pures before. Thanks in advance to anyone who can help us out.