Do I need more cubes to learn better?

[CriticalCubing]

Not at all. I average 17 sec and I have about 5-6 speedcubes and other local cubes. It is not necessary unless doing multi blind!

 

[RobertFontaine]

The latest best 3x3 comes out about every 5 minutes so it won't take long to have a stack of cubes in the house/car/bathroom.