Frequent business traveler Ken Denson vacations in Maui once or twice a year and never pays for a hotel room.

Denson, a Los Angeles-based tour manager for bands, collects points in more than five hotel chains' frequent-stay programs and cashes them in for free rooms. "I used 15 free nights at hotels in 2006 and did not come close to using all the points I had earned for the year," he says.

Frequent-stay programs are popular, but it's difficult for Denson and other business travelers to determine which one is best. The programs are frequently changing and have different standards for earning and redeeming points.

Points in some programs, such as those of Hilton, Starwood and Red Roof, expire if a member's account is inactive for many months. Policies also vary on the number of free rooms chains make available to frequent-stay members and the high-volume days on which free rooms aren't offered at all.

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