Heh, actually, almost zero. My win/loss shows $1000 in 2014, $400 in 2015, and $0 in 2016 and 2017. I hadn't gone in a couple of years. I only started opening their email offers in the last few months. Looks like every quarter I'm offered 2-5 nights depending on the property (I think it's 2 free nights at Caesars, or 3 at Paris, or 4 at Ballys, or 5 at Flamingo or Rio), plus I was given an extra week around Thanksgiving and Christmas I'm not using. Pretty sure after this trip this weekend, there's another offer for Jan-March in my queue but I don't think I'll be able to use it. And Super Bowl weekend looks like there's an offer for another stay and tickets to the sportsbook watch party.
Yeah, free hotel, plus refund of the resort fee in hotel credit & slot play, and I'm still complaining about the parking fees and getting hit with the resort fee in the first place. What can I say, I'm a cheap SOB.
It's a vacation, I take the lady friend and we get away for a few days. There are plenty of places within driving/short flight distance... besides doing stuff here in LA, there's San Diego, San Francisco, Palm Springs, we'll even go to Portland. Las Vegas has competition they're not used to. For them, the room is going to sit empty anyway so having me stay there free doesn't cost them anything (I even opt out of maid service so they don't even have to pay someone to clean the room), and in what they charge at the restaurants alone they're making money off me.
If they'd offer free stays at the SoCal properties, I might visit there more often than I get to Vegas, but so far the best they're showing me is $50/night during the week or $125/night weekends. I guess I can understand the SoCal hotel has limited room capacity so there actually might be some demand.
If anyone has comps they are willing to share I'd take them with major thanks and kudos.
All we need in life are the simple things. 
