Background size to improves runtime improvements

I wanted to ask a simple question to improve the runtime of my mobile games.

Is it better for background objects to use 128*128px tiles (less background objects) or 64*64px tiles (more background objects) ?
I'm Always looking to improve my games so i was wondering if i was right to use 128*128px tiles.

Thanks.

Tiling is good, giving more chance to use the same texture in multiple location not need to be 128x128, can be 256x256 and all depends in the size which

is more repeated.

Is very important if the game will scroll that these textures are power of two, 64x64, 128x128, 64x128, 128x256