Both my Ts reply back to all my emails. T replies the next morning, L replies before noon the next day. T only replies short replies, L usually does long replies. Both T and L require me to include what I want in a reply (i.e. encouragement, reassurance, something specific, etc.). I do not get charged for emails, and I can basically email as much as I want. Though, since T isn't my active T, I'm only supposed to email her once a month.