NO MORE CLUBS!!!!!
If you want to become a better golfer, really want to work at it you should play with half of your clubs. It will teach you to be a better ball-striker and you will learn more shots that you could use on a daily basis.
Lets say with your normal iron swing you hit an 8 iron 150 yards(85-90% of maximum swing which is how hard you should swing your irons) you should learn to hit your 6, 7, and 9 irons all 150 yards. I am not talking about good players that can also hook into the wind, cut it into the wind hit knock-downs and all types of shots with their irons. I am talking average joe that shoots 90 could REALLY improve his score by learning to hit one club less and one to two clubs more with different ball positions the same distance.
For me I hit my 8 iron 163 yards. I can hit my 9 iron that far, I can hit a 7 iron that far and I can hit a 6 iron that far. My grandfather made me play golf with half my clubs every time we played. I can hit a three wood high or low same with the driver and hybrid. I am a better player for it and it would help average golfer as well.