Hi Sisu,
Business owners often include Restraint of Trade (non-compete) clauses in agreements and they do so to protect the goodwill of their business, their business interests etc. However, the restraint of trade (non-compete) provisions have to be reasonable for them to be valid and enforceable.
The Courts, in determining whether a restraint clause is reasonable, look at whether the clause protects a genuine interest of the business and whether the limitations with respect to time period and geographical area are no greater than necessary to protect interests of the business. In Hanna v OAMPS Insurance Brokers Ltd [2010] NSWCA 267, the court held that a 12 month restraint period was sufficient and was probably the maximum that could be applied. The Company sought to rely on a 15 month restraint of trade clause.
In short, the restraints have to be reasonable for them to be valid and enforceable. Non-compete clause for a period of 5 years, in my view, would be held unenforceable by the court.