I have around 100 ads at the time I'm posting this so I use the Craigslist email system because it lets me keep track of multiple conversations with multiple buyers. I don't want to program number into my phone like kayak girl, ryobi dude, dog crate chick, netgear guy, etc.
Face to face, cash deals only. Sold as-is. No shipping, money orders, payment processing apps, etc. I get a lot of replies from scammers like "text me at [number]" or "Is the item still available?" so, I'm sorry, but I can't respond to that kind of thing.