It also partially excludes those who don’t earn a lot, at least where I live (Ontario, Canada).
You earn around 30k a year? Hey, you get some benefits! Two people earning 50k a year? Well, obviously you don’t need those benefits anymore. In fact, let’s cut your collective returns down by a nice $342.
Nothing changes if you’re just roommates, but they sometimes really want to verify that you’re not secretly common-law. You can get in legal trouble if you get caught.
It was kind of messed up the first year that my partner and I filed taxes together, to be honest. We couldn’t do that until we were living together for 2 years (federal government), and 3 years (provincial government).
They didn’t tell us to both save the entire previous year’s GST, and it ended with us having to pay between $500 and $700. That was a fun birthday suprise. The bad parts of common-law start before any of the benefits, apparently. They also seem to start before you can legally file. I tell everyone who I know is moving in with a partner, because fuck that noise. I wish someone told us earlier. Anyone, really.