Just to share an experience I had, long before I joined REIN, I was in a similar situation. My principal residence mortgage was due for renewal, and my bank offered what appeared to be the posted rate (not a very good rate at the time). I knew I had at least a month to think about it before I accepted, so I just waited and didn't reply to the bank's offer, mainly out of procrastination.
A couple weeks later, the bank called me back, notifying me that they have some "special deal rates" to offer me. I called them back, and they immediately offered what was a far better rate, which I accepted. That must have saved me 0.3% or 0.5% , just by not responding to their first renewal offer, making the bank think that I was shopping around for a better rate.
I learned the exact same lesson that A.Sanchez is sharing above. Luckily, it saved me some $$ over my next 5-year mortgage term.
It's definitely worth your while to find a better rate. I would suggest that you work with a mortgage broker. Why do the shopping around yourself if a professional broker can do it for you? Mortgage brokers do save you tons of time. At the very least, you should find out what is the best rate you can get, and then ask for that rate at the bank. If you can find that rate, the bank will know that you're willing to leave them for that better rate. Your bank is fully aware of the competing rates out there, and should be willing to offer it.
Good luck.
George