I made my own gear sets back in the day.
/use Sword
/use Heavy Leg
/use Large Shie
I used the shortest names I could so it would fit into one macro. Then I learnd about /click, so I just made 2 macros. I kept the gear in order, so if I changed out a shoulder or hands, I knew exactly where to look for it.
Then I moved on to Outfitter, and have never looked back. I LOVE it, so much. Yeah, there is a built in version, but I like that you can push the button (either macro /outfitter wear Healing, /outfitter wear Tanking or it has a button bar) and it will change when it can if you are in combat. It will change if you put conditions on it, primary spec. So if you change to tanking spec, you don't have to remember to change your gear, it does it for you. BGs or PVP flagged. It has crap tons of other condtions that it can check for (riding, swimming, fishing, etc), but I just use specs and BG/PVP. I love not forgetting to change when I do WG. I love not trying to tank in my healing gear.