Depends on how advanced you are and what your overall goals are. Most guys can most likely attain their goals with just a simple Test cycles, or a couple Test cycles.
But like Nelson said, stacking is trying to find the balance between anabolic and androgenic properties of steroids, and then finding the synergy with what you use. Then you also have steroids like Tren that is both a strong anabolic and a strong androgen.. so stacking multiple compounds with it just become redundant.
For example.. the most common stacks (excluding the test base) start with a steroid that is your primary anabolic compound.. these are typically Deca/NPP, Tren, EQ, or Primo.. and are responsible for actual muscle growth, and then you would typically stack one of those with a DHT steroid like Masteron or Winstrol, which are mostly strong androgens that will help with hardening and strength. So making a stack like that would both giving you muscle growth, combined with hardening and strength. That is pretty ideal.
There is an endless amounts of stacks out there.