According to :
Any electrical panel with breakers that old should be considered
suspect, irregardless of brand. If you could just replace the breakers
with new ones, you would be perfectly fine. However, that's not
economically viable in your case, so replacement is probably a good
idea.

Actually, it is quite viable. While "Federal Pacific" "legacy
replacements" in the US are quite expensive, "Federal Pioneer"
in Canada is no more expensive than any other breaker, and cheaper
than many [+].

If you live near the border, or find a mail/Internet order source,
it's quite doable.

The Federal Pioneer breakers are fully approved to US standards.

[+] I think somebody's making a fortune shipping Federal Pioneer
to the US and making a fortune off people who don't know any better.
--
Chris Lewis,

Age and Treachery will Triumph over Youth and Skill
It's not just anyone who gets a Starship Cruiser class named after them.