To add to the above, it also depends where you play. At some of the higher end properties such as Bellagio, $25 average bet for 4 hours may get you a room at the casino rate and perhaps a comp coffee shop meal. The same play at a downtown casino may get you a free room with limited or even full food and beverage. $100 players are treated well on the strip, but are given red carpet treatment downtown.
It also helps to get to know a casino host who is authorized to comp beyond what you may be entitled to based on your theoretical losses.