Well first off the best place to get visa information is from the government website, they are never wrong!
http://www.immi.gov.au/Secondly, you do have a few things wrong so hopefully I can correct some of it.
Once you are granted your PR visa it is valid for 5 years. You will need to visit
Australia (even for just a day) to validate it. You must validate your visa in the time frame they give you, which is usually 1 year from the date of when you did your medicals or police checks. If you did either of those things early you'll have less time to validate, some people only end up with a month or two to validate. We had 9 months as we did the medicals and police checks later on in the visa process.
Now, to keep your PR visa you will need to actually move there some time within the 5 year period. You could wait until the last month before it expires to do it if you like. If you do not move to
Australia within the 5 years it WILL expire.
However, assuming you activitated your visa in the time given and you've moved there within the 5 years then you're ok. Once that 5 years is up you still keep your PR (as long as you are living in Oz) but if you want to travel outside
Australia you will need an RRV (return resident visa). It's the visa label itself that expires, the PR is still good as long as you're in Oz. The RRV visa costs about $100-200 I think and you'll need to be living in
Australia or have significant ties in order to get one. As long as you have actually moved there it's not an issue. Basicallly the RRV means you keep your PR and allows you travel outside
Australia as long as you have the RRV.
Once you have PR you need to clock up a full 3 years living in
Australia to be apply to apply for citizenship. This does not need to be within the 5 years of your visa label, although for most people it is. Once you've clocked up 3 years (out of the past 4) living in Oz then you can apply for citizenship.
I'm sure that all sounds complicated so here's an example.
You get your PR visa and validate it 6 months later (within their timeframe).
Then you go back to Canada for 2 years before you make the big move to Oz. Once living in
Australia you manage to clock up about 2.5 years living there before you visa label expires. You still have PR but then you'll need an RRV (return resident visa) to travel outside
Australia.
Once you hit the 3 year mark you apply for citizenship, which could take about 6-8 months to get. Once you've got citizenship you're free to do what you like.
So to clarify what you said, the PR visa does not automatically renew for 5 years. It is in fact good forever once you are granted it but the catch is that you have MOVE to
Australia within the 5 years and continue to have ties there. Furthermore your PR is always good as long as you're here, it's just your ability to travel OUT of the country and return that is a problem, hence the need for the RRV.
As for your question regarding the sponsorship, I have read that it is more of a moral obligation although if they think you never intended upon living in your sponsored state there could be issues. Like, if you got the NSW sponsored 176, arrived, and within a month left for another state. You could have issues if you couldn't show that you at least tried to stay and work in that state. But as far as I can tell from reading on the internet it's really only a moral obligation and if you do move to another state there's not much they can do. Alternatively I think after a decent amount of time you might be able to ask the state to release you from the obligation if you've made an effort to stay but can't for whatever reason.
I'm not an expert in the sponsored visas (or any for that matter) as they are just becomming more important with the quicker visas (as opposed to the unsponsored 175). Have you checked to see whether you're eligible for the 175 independent? If you are there are no ties whatsoever to any state, although it would take longer to grant I think.
The best place for information is the British Expats website as there are so many people on there and lots of knowledge there too. It is the only place I go for information as it's pretty reliable overall. It's not just people from the
UK either, there are a few Canadians (me included).
http://britishexpats.com/forum/forumdisplay.php?f=54This is the link to the immigration section:
http://britishexpats.com/forum/forumdisplay.php?f=32Here's a few relevant threads:
http://britishexpats.com/forum/showthre ... ored+statehttp://britishexpats.com/forum/showthread.php?
t=600413&highlight=176+obligation+to+sponsored+state
Lastly.... using a migration agent is probably not necessary. It really depends how comfortable you are with the forms and how much time you want to put into it. I did our application (for the 175) myself and it was relatively easy although I did have to do a bit of double checking of information. If you're not sure what to do I would do an initial consulation with an agent (usually free) and see what they have to say.