It really depends on what type of weight workout you want to do. If you want free-style you usually work body parts more often. Also there is a dfference between maintain what you have and what you want. If you want to stay with what you have, you don't have to work it so much, to keep it. To get it, you got to work harder.
If you want tried and true strength training, you could do the GS series one week, then muscle max, and ME the next week (rotating days), the week after that S&H, then PS for the next week. Then fit your cardio in there anyway you like or whatever way time works for you. As well as stretching, make sure you do Stretch max a few times a week. This will help some with sore muscles as well as make you less injury prone.
If you do free-style that's a whole different thing. It's nothing to work your abs 5 or 6 days a week, your lower body 3 days and your upper body 3 days. One day off with a stretch or just rest, then start all over again.
So basically do what feels best to you, and you get the best results, as everyone is different what works for me, may not work for you. And play around with it don't be afraid to switch and change and see what happens.
Kit