It is why i like contracting and find it so more honest on my and companies side of things. They say "work here for 6 months", I say "ok" after that they can ask me to stay and I can agree or not or they can not renew me - either is fine.
Being an employee, generally (not always but it must be 99% of places) you need to:
1. love the company you are working for. 2. be willing to receive emails constantly. 3. not be attracted to other companies. 4. accept begin laid-off as and when the company desires.
Contracting on a fixed length contract, I am almost guaranteed to have work until the end of that contract - working for a company, 0 guarantee i will have a job in 1,2,6,12,18 whatever months.
(how the hell do you get lists on multiple lines here ha ha)