tedster - 5:58 pm on Mar 18, 2010 (gmt 0)

Deciding whether the effort is worth it depends on how problematic your current situation is. If it's not currently "broken" then the fix is really just insurance against possible future problems.

If you do see current problems, the ideal is to fix the canonical issues on your own server - you can never be certain that Google will execute the canonical tag exactly the way that you hope, and they only take the canonical tag as a "suggestion" at any rate.