I wrote my T (snail mail) a couple times a week for 5-6 years before I decided to "quit" (cold turkey :-) and only talk to her during sessions. Changed therapy (and me) for the better right away. But it takes time to be able to do the direct one-on-one thing like that, to be "there" when you're there, and experience the other person there at the same time and both know/experience the relationship together.