You should enter Australia before the first entry date which is provided on your visa or else your visa will not get validated and it will expire. Once you have entered Australia and returned back, the visa will be valid for five years.
What is the next step after I get Australia’s 189 visa approval?
I was invited to apply for Australia’s 189 visa and my case was approved. However, currently I do not have plans to quit my job in my home country and relocate to Australia. How long is the 189 visa valid? Do I have to take any actions before a certain deadline in order not to lose my eligibility?
Congratulations! Your hard work has paid off!! Please follow the next steps: check your visa grant letter, and it should say, "Must arrive before [a date]"; since you have work, take a holiday; once you arrive in Australia, you will have five years of unlimited travel. Recent issues are with people who don't live in Australia for enough days/time. However, we have a pretty good track record with helping people with that also.
You will need to enter Australia before the initial entry date, which will be listed in the visa grant letter. This will activate your visa. Otherwise, you will need a letter of facilitation in order to make your first entry to Australia. The visa will then have a five-year travel facility, so you will have five years to relocate to Australia before you will have trouble entering Australia again. It is possible to apply for a resident return visa after the five years have elapsed, but this can be difficult unless you can show established ties to Australia. It is better to relocate to Australia within the first five years after the visa grant.