I can email my T though she can only check emails during work hours. She emails me all throughout the day - I use it quite a lot actually and she worries if I *dont* email her. I am multiple, though, so my alters and I use it to keep her up to date on all of us and what's going on because we only have 2 hours a week face to face.
I can call her office and leave voicemails. A lot of my littles like to leave her messages if they miss her. She always gets back to us as soon as she can, unless it's after 530/6 and she's left.
I can call her at home - I almost did Saturday after being suicidal but I couldn't bring myself to do it! She encourages me to call her at home if I need her (whether it's due to fear of harming myself or if I just have fear of abandonment kicking my butt and need to hear it's ok)!