You should be fine. Shut it down once a week to allow the memory to be freed up, otherwise as the week progresses you may start receiving memory errors because the system is losing track of where data is written to.
I use hibernation on a daily basis and shutdown probably once every two weeks. If you can, use hibernation. It takes a few more seconds to wake up from it, but it is a better alternative to sleep because it writes the information stored in memory to hard disk so you aren't using battery life keeping memory charged (as when memory loses charge you lose the data).
This publication by microsoft will help:
Sustainable Computing: Sleep or Hibernate?