I go about 5 days a week (and run or walk on my days off). I used to do lighter weights more frequently but now I do a really strenuous weights workout one to two times a week (for about 45 mins). Apparently unless u really rip apart ur muscles (so u really feel it the next day) you won't do much, so I do heavy weights, more reps and 3 sets of each. Then, for the rest of the week, I focus on cardio. One step class, one body attack class, and two sessions on the cardio machines. Usually do abs and yoga streches about three times a week too.
That's on a good week hehe
but the point is you should be really sore the day after ur weights.