How many Particle effects affect performance?

If I have 2 or 3 game objects, would having 2 or 3 Particle effects components attached to each of them and played intermittently hurt performance too bad? Especially if the particles are small in number and not too large in size or count?

What's the general recommended practice for handling different particles?

 

It depends on target and setup. A few components should be fine though.

In general, it is better to have:
- fewer systems
- fewer modules per system
- fewer expensive modules (noise is more expensive than color over time, for example)
- fewer particles per system
- fewer cullable visible systems, see here: https://blogs.unity3d.com/2016/12/20/unitytips-particlesystem-performance-culling/

In some cases, an optimization is to reduce system count by merging many similar individual systems into one system and emit particles manually, but this can increase complexity.

But pragmatically speaking, make it look good first then consider its performance impact. It really may not matter especially if we're only talking about a few systems. Profile on your target hardware.