Can someone help about performance?

Hi!
I have a begginer question about performance. I need to kwon how good, and fast my game will run on a specific plataform, and I don't kwon how, or where to start. I'm thinking in a 2D game for mobile, and a want to use some effects, but how can I know if these effects are too much for the plataform I want to run? or, how can I know the minimum hardware the player need to have?
I'm glad if someone can show where to read about performance with these focus.
Ps.: Sorry about my english error... =]
Thanks!

 

......by testing it on the device?


EDIT: For general information, there are some performance helpers/guidelines. Probably many more around the web too:

http://docs.unity3d.com/Manual/OptimizingGraphicsPerformance.html
http://docs.unity3d.com/Manual/iphone-performance.html

 

I think about test... but I'm feared about have to rework TOO MUCH, after I discover that the game is running very bad on some devices... so, I would like to kwon a little about that before I start.
Thanks for the links Steve.
=]

 

There was a really good article/blog post once with some great optimisation tips. I'm trying to find it for you. Will post a link if I do.

 

ok... i'll search, today, about optiomization tips too =]
thanks