Writing all the functions into function lib Or Reusable Action ,which approach is bes

[JyotiRanjan]

Hi ,
I am going to automated one of my applications having near to 200 Objects. It is advisable to create all reusable functions into Function Library. Or I can create all functions into Reusable Actions.
Which approach takes more memory?
1. Writing all the functions into function lib,
2. Writing all the functions into Reusable Action.

[basanth27]

Would you please elaborate on writing all the functions as reusable action? How would you do that?