Several girls I punt with have saved my number. They do it to know it's a regular or a good punter.
My regular girl has my number and my first name. That way, when I send her a text, she knows who I am and that I will turn up. I have her number, but only use it to send texts and call her to tell her when I've got off the bus and started walking to her place. At the beginning she did text me, but she's stopped doing that. She's never called me.
Nobody else I've visited has ever called or texted me.
I always delete my text threads and logs after making a booking.