how can i simple change upload folders to %year%/%month%/y%?

Is there a easy way to do that?
Godaddy have a silly limit of 1024 files in one folder and my client upload more than 500 and with the thumbnails we get lot over the limit.

If im able to changed folders into %year%/%month%/%day% i will be safe about that limit

Also another question is if i can make wordpress to generate thumb only when needed. For example home slider will only use 10 images i dont want the other 1000 images have that thumbnail generated.

Thanks for the help!