Where I am in British Columbia, there are sound isolation requirements in the building code so the landlords can't be cheap...but it doesn't help with older or non-permitted work.
A quick google suggests that British Columbia's building code only requires STC 50 which is "you can hear but not understand a neighbor's loud conversation" levels of isolation. Though maybe your city has stricter requirements?
Only 50? I think that's pretty good when considered on its own but STC doesn't look at the whole picture. STC ratings and requirements for discrete wall and floor assemblies are a thing but with suites/party walls apparent STC is what mattered whether it was the provincial code or local bylaws. ASTC is king.
