5 year term insurance is life insurance where premiums are level for 5 years. At the end of 5 years premiums will increase dramatically.
Technically, 5 year term life insurance would be suitable when you need life insurance for 5 years or less. Your premiums would be level for 5 years after which point the premiums will increase. However as you no longer need the insurance at that point you can simply cancel the policy. This would allow you to obtain life insurance inexpensively for the 5 years or less that you need the life insurance.
However in the Canadian life insurance marketplace, 10 year term life insurance is a far more competitive product. That means for most of us it would actually be less expensive to buy life insurance where the premiums are level for 10 years rather than level for 5 years. The exception to this may be males age 50 an older, where 5 year term may be less expensive than 10 year term.
You should consider 5 year term for needs such as covering short term loans (e.g. business loans, lines of credits used for short term mortgages) or if you are looking to cover your family for a short period of time. Again though you should also shop 10 year term in these cases, as 10 year term may be a less expensive option. When purchasing 5 year term insurance it is also vital that you only purchase a product with conversion.