Here is a good article on the CBC website that talks about breaking your mortgage to refinance with a better interest rate.
I would generally agree with the points made in the article, except that the last point regarding splitting up the mortgage into multiple components I would not necessarily agree with. One reason for this is that the mortgages are typically collateral charges and makes it more difficult to switch the mortgage at the end of a term.
It can be a good time to refinance your mortgage if your penalty is small. If you would like to discuss further your circumstances to determine if it would make sense for you, call me and I can better advise you on your individual needs.