This might be just in BC but BCSA directive D-E3 070302 6 states
that a single commercial or residential tenancy would have to have its own main disconnect. I was once told to upgrade an existing load center to a main breaker panel in a renovation that was quite substantial but since then I have never been asked.
My question is where do they draw the line? Which renovations should include a panel upgrade and which ones will be grandfathered. My opinion is that if the panel is existing then it stays as is.

What are your experiences with this?

Here is the text from the directive:

1. In multi-unit buildings where the feeders are supplied from an electrical distribution that is
in a separate building, room or enclosure the requirement for over-current devices and
control devices to be “readily accessible” is not being met. Interpretation of Rule 14-406 is
to require installation of a single main disconnecting means for the loads within the area of a
single tenancy, ownership, etc. (occupancy). In multi-unit buildings where the feeders are
supplied from an electrical distribution that is in a separate building, room or enclosure,
each occupancy is to be provided with a main disconnecting means that is within the
occupancy. This requirement is intended to improve safety by providing ready access by a
qualified person to the single disconnecting means controlling all electrical equipment inside
the occupancy.

Not required in Saskatchewan. That "interpretation" is a pretty big saddle to put on this little horse:

14-406 Location of control devices
(1) Control devices, with the exception of isolating switches, shall be readily accessible.
(2) Remotely controlled devices shall be considered to be readily accessible if the means of controlling them are readily accessible.

Isn't the main an isolating switch?