GF sends texts, every day, i.e "Good morning baby I hope you have a great day today ", as well as good night texts.

I don't always respond to these and she doesn't let up, not that I really mind it.

I sometimes say "I appreciate it, keep that ass in good condition for me today."

Or just "I appreciate that" followed up with a nick name "baby, kitty, etc"

What are good ways to respond to these when I decide to respond?