Earn 15k tier credits from gambling/hotel spend in one calendar year. This can be made easier thru daily bonuses and occasional promotions/gifts that occur sporadically. https://www.totalrewards.com/content/cet-tr/en/earn-and-redeem/with-total-rewards.html
I don't keep detailed records like some, but I'm roughly even on the year, maybe even up a couple hundred bucks. Just made diamond on my last trip. Hitting a 25 cent royal on VP each of my last two trips certainly helped though....point being that, if one plays smart and takes advantage of the daily bonuses and other promos, and is one of the lucky ones that gets a "loyalty" gift, diamond can be achieved with maybe only a few thousand in theo.
I was actually up when I made Diamond thanks to a $10K jackpot in February, but to make 7*, well, that's a different story . . . .
Yeah, I agree with grosx2, it's really not that hard if you can find a good machine that you can "cycle" a lot of coin in through. To answer your question though it requires $150,000 coin in on Video poker, or $75,000 coin in on slots. Or, put in another way, you need 15,000 "Tier" credits. $10 coin in on video poker equals 1 tier credit, and $5 coin in on slots equal 1 tier credit. With the current "bonus's" you receive bonus tier credits based on your play per day. Not sure what levels you play at, but for instance if you earn 2,500 tier credits in 1 day, you get a 5,000 tier point bonus, so you could achieve diamond in 2 days at that level, or, if you are more of a High Roller, earn 5,000 tier points in 1 day and you get a 10,000 tier point bonus. Check with the property you are gambling at to see when their "day" starts and stops, it is not midnight-midnight, but usually ends early in the morning like 4:30 - 6:30 am. When you put your card in a machine it will display information about your current status, points earned that day, etc. Now, having said all that, you can "buy" diamond status for around $400 (Last I checked) by joining something called the Founders Card. If you do a search on this forum you will see a more detailed thread about this.
OK, a "refinement" of what was said above. Making diamond can be done with only $25K coin in on slots IN A (CET gambling) DAY. That's 5000TC (plus the 10,000TC bonus) or "Diamond in a Day" For VP double those amounts. I find that two 2500TC days are easier (2500 + 5000 bonus TC each day for two days), but the same amount of coin in. One problem with the Founders Card is although you get the Diamond Status, AFAIK you don't get an TC with it, so advancing your level is more expensive. However, from what's I've seen, Founders Card members aren't really interested in other than the base Diamond level privileges and are not "gamblers".
I would just play for fun and if you make Diamond, all the better. I'm Platinum and that's after a good amount of blackjack, and I've lost enough LOL. Enjoy Vegas and have fun, you may make it inadvertently.
Not true--very much a gambler, but do not have the bankroll at this time to truly earn Diamond! (but enjoying the benefits!)