If your T says it's fine, then it is. A therapist wouldn't do something they thought was crossing a boundary or if it was too much trouble for them. Personally, I never contact my T outside of therapy. She has rung me a few times to cancel and once to see how I was, but that's it. I never initiate it. For me though, it's because I feel majorly uncomfortable talking on the phone and because I don't pay to see her and I know she's really busy so I'd feel uncomfortable taking up her time...but if I paid for it, I'd want my moneys worth.