Hilton Hotels/Gold/Diamond...
I stay at Hilton family properties around 75 to 100 nights a year. I am regularly upgraded at almost every property except some lower end Hampton and Homewood suites. I think the items that count are status (earned vs credit card), repeat status at the same property, and most importantly appearance and attitude at check in.the agent has a lot of sway on check in. I have also on occasion when not upgraded automatically asked politely and then was granted a nice suite or better. Short 1 or 2 night stays are more frequently upgraded then longer stays and any stay off 5 or more days typically requires advance Co ordination to obtain any upgrade of value. (if traveling on family vacation I will book in advance and call and ask the hotel directly if there is anything they can do )