I called my T maybe 5 times in 18 years I saw her (not including initial time to set up appointment or other "technical" considerations) but my absolute favorite, after I "got it" was when I was going to be late to a session and wanted her to know so she didn't have to wonder where I was.

Normally I would have just driven faster or worried about myself and how I hated being late, berating myself for starting out too late, etc. but I finally understood we were a "team" and how what I did and felt could impact our relationship. If your T needs to know something to be on the same page you are, tell her! If you think you might benefit while struggling with something from talking to your T, call her!

However, if there is just the "wanting" of your T (and you don't know what you would do with her if you caught her :-) and you feel you would be devastated if she didn't answer/call back quickly enough, that it would mean she didn't care about you, then you probably should work on those things a bit harder inside yourself and with her in session. Your T is there for sharing information and working together in your struggles; not for "rescuing" you. The trick is being able to see your T as a separate, interested person with "needs" in the relationship too.

It was easier for me to learn to talk to my T when I was in session first, and then I was better able to call her when I needed to because I didn't have to "find" the connection anymore, it was just naturally there in all communication with her and was more often about our work together.