Does anyone do this with their T?

To have a set fee/length for e-mails?

Should there be a fee to send an e-mail/for her to read it? Or only for her to reply to it?

What should that email fee be, if the session fee is $120? (Or 87.50 when insurance pays).

She's expressed a lot of resentment regarding my emailing/texting, so I'm trying to stop doing it completely, but I know there will be times when I give in, so I want to have a payment schedule in place for those times.-so she doesn't feel taken advantage of for me getting too much of her time (for free) outside session.