Making sure you have the best rate is tantamount.  Being able to switch your mortgage at maturity (renewal date) to another lending institution without cost has the marketplace busing with anticipation.  Todays growing trend amongst mortgage seeking Consumers is to shop, shop, shop.
Although I don't begrudge you the right to shop, you should know that most lending institutions will feel obligated to run a credit report on you before issuing a pre-approval, or a commitment.  When you inquire for rate discounts here and there, each lender will ask you to sign on the dotted line, allowing him or her to do a credit bureau search against your name.  The lender will admit you are under no obligation to take their mortgage.  However, the inquiry at the Credit Bureau is registered.  You may feel the more institutions you visit, the better your chances of finding the best rate.  Actually, the reverse is true.  You should know that the more inquiries there are on your file at the Credit Bureau, the less likely you are of finding the best rate!  Why?  Lenders have a name for multiple inquiry clients . . . CREDIT SEEKERS!
The more often lenders inquire on your name, the lesser of a credit score you will receive.  One way around the problem is for you, the Consumer, to obtain your own credit file at the Credit Bureau (Consumer Inquiry) and bring the report with you when you are shopping.  Do not sign the credit application but rather have the lender issue a pre-approval based on the validity of your credit report.  This will enable you to shop to your heart's content without arousing negative vibes at the Credit Bureau.  Once you have picked your lender of choice, then and only then, do you permit them to do their Credit Bureau inquiry.   You can achieve the same result by shopping with one mortgage broker.  That credit inquiry will be shopped to various lenders who will accept it as an original.

When you initially buy a property, and you need a mortgage, the mortgage lender may insist on a recent "building location" survey.  These surveys cost about $1000 in an urban area, and are likely even more expensive in outlying areas. Eight cases out of ten, lenders will accept an old survey with the Vendor declaring that no changes have occurred to the property since the survey was done.  The purpose to the survey is the guarantee the building set backs from the property lines conform to the local bylaws, and to show that neither you, nor your neighbours are encroaching on one another's property.  Although it is preferable to have a survey, often a visual check of the lot is good enough for you to believe that everything is in order.  If the subject house is in the middle of its lot, and your neighbours' house is in the middle of that lot next door, and there are no signs of young trees or new fencing, chances are everything is OK.  The lender however may insist on a survey to prove the integrity of the lot.  Spending an additional $1000 on day of closing (that's when you actually take possession of your purchase) can be imposing.  An alternative to a survey is now possible in Ontario and some parts of Quebec, it is called "title insurance."
Title insurance is meant to protect the lender in case of title defects, that a survey would likely have caught.  Title insurance can be purchased by the lender for a fraction of the cost of a survey.  It should not be construed as equivalent.  The survey will protect you at the onset, while the title insurance will protect the lender in case of future trouble.

When you purchase a property, money is going to be tight.  The last thing you need is a surprise tax billing.  In most cases in Ontario, if your down payment is less than 25%, your lender will insist on you paying the property taxes through your mortgage payments.  And in most cases, you will be obliged to prepay your taxes by at least four months.  The reason why the taxes must be prepaid is because your municipality wants your whole year's worth of property taxes paid in full by September.  Your lender knows that tax arrears take precedence to their mortgage.  Be aware.