How do I store sprites in memory corectly ?

Hi guys, from what i understand is that C2 stores all sprites of the layout in the memory. My questions are this: Does it store from layout to layout...or ALL sprites of the entire game ?

Is it wise to do this: One layout with all sprites that I do NOT use as game layout...but just as canvas where to copy and paste soprites for the other layouts ? Example... if in layout 5 there are no ememies. I simply do not copy paste them there.... is that a correct procedure ????

thanks

https://www.scirra.com/manual/183/memory-usage

Layout by layout only. A sprite will only be loaded into memory if it exists on that layout.

Worth to mention that if the sprite which has been loaded in the current layout also exists in the next layout, then it will remain in the memory and won't be reloaded (there is no need then). All other sprites will be released from the memory.