Best animation speed?

Hi,

Just wondering if I have a 4 frame animation.. what would be the best "animation speed" to use in terms of performance.

I'm thinking 6 ... 12 looks good too... but might overload?

Ofcourse, higher speed is making it look smoother.. but in terms of a game that needs to be played on mobile, wondering what other devs feel is a good speed that doesnt kill performance on a decent mobile these days.

Also, does ping-ponging take up more resources?

Thanks in advance :)