Optimizing duration of participation in health promotion programs has important implications for program reach and costs. We examined data from 355 participants in EnhanceWellness (EW) to determine whether improvements in disability risk factors (depression, physical inactivity) occurred early or late in the enrollment period. Participants had a mean age of 74 years; 76% were women, and 16% were non-white. The percent depressed declined from enrollment to six months (35% to 28%, p = .001) and from six to 12 months (28% to 22%, p = .03). The percent physically inactive declined over the first six months, without substantial change thereafter (47%, 29%, and 29%). Those remaining inactive at six months had worse self-rated health and more depressive symptoms initially; a subset of those increased their physical activity by 12 months. These data suggest that enrollment could be reduced from 12 to six months without compromising favorable effects of EW participation, although additional benefits may accrue beyond six months.