Changing Routine every 4-6 weeks?

I've heard a lot of people on here say that you should change your workout every 4-6 weeks or so because your body adapts. But I am wondering what you change. Add more weight or change exercises all together? What do you guys usually do?

change the training split you are doing every four to six weeks......weights and exercises can, and in my opinion, shouldbe changed weekly.

So just switch the days around?

No, match different bodyparts together.

You can change a lot of things, number of sets, reps, weights etc (I recently changed all three myself... dropped the weights 5-10 pounds and doubled the reps per set and dropped 1 set).

There are a lot of things that can be changed, even the amount of rest time you give yourself can be a pretty significant change. There are also a lot of different training philosophies out there too, it can be good to try out new philosophies now and then to see what works for you best and provide enough of a change to keep your mind interested in what's going on.