I never played with mods, but I'm considering isntalling Hydrocraft. Do I have to start a new game?

[ZonaryQuasar]

Title!  

I'm playing with a chracter for a looooong time, and I'm heavily inclined to install Hydrocraft to see all the new things that the mod adds. Can I install and use with my existing save or do I have to start a new one?

Thanks in advance!

[MrDany]

Global mods like Hydrocraft need a new save, because items will not spawn in boxes, tables, etc.(maybe) NecroForge can work