You've probably already tried to understand the rules for yourself. The information is out there... somewhere.
But it's scattered, incomplete, not always up to date, or couched in legal language that's hard to understand.

Best of all, you never know if they really apply to you.

So you ask around, look for groups on Facebook, listen to advice - sometimes useful, sometimes risky.
And you may be thinking of consulting an immigration lawyer, but the fees are often too high just to find out if you're eligible.