For many dynamic 3D sounds, reuse AudioSources instead of constantly creating and destroying them.

Pool idea:

Pool
├── AudioSource 1
├── AudioSource 2
├── AudioSource 3
└── AudioSource 4

A free source can be found with:

if (!source.isPlaying)
{
    // reuse it
}

Useful in shooters, impact-heavy games and dense ambient audio.