Most people in Ontario these days will buy a property without a survey, or without an up-to-date survey. Most of the time, this will not be an issue. However, there are times when nothing replaces having that knowledge ahead of time.
Where a survey really matters is where your boundaries really matter. If you access your property by a deeded right-of-way, you should get a survey to ensure that the right-of-way exists where it appears to be on the ground. If you think you are buying waterfront property, you will want a survey to ensure that there isn’t a municipal road allowance running along the edge of your property in between what you own and what the municipality owns.
Basically, if there is something that truly matters to you, you should very seriously think about getting a new survey if the seller won’t agree to give you one, and keeping your offer conditional until the new survey comes in. Sometimes, what you don’t know can hurt you.