Insurance providers group all offenses into three categories. A conviction will either fall into the minor, major, or serious table. All offenses in a category will receive the same surcharge percentage.
Example: Minor (0-5%), Major (15%), Serious (100%).
In terms of insurance, it's best not to judge an offense on how it sounds on its own, but rather who it's grouped together with since they'll be treated equally.
All turning offenses fall into the minor category. These I'd consider your every day type of tickets. Signaling offenses, seatbelt, stopping, speeding (less than 50 over), etc. If you've ever received any of these type of tickets before, you'd know what to expect.
Your average driver is probably unaware that Careless Driving falls under the serious category. It's considered the worst of the worst. Speeding (50 over), racing, impaired, failure to remain, no insurance, driving while suspended, etc.
With a serious offense, there's no guarantee that your provider will continue to insure you unless they also offer some form of high risk insurance. If not, you'll be searching for one or you'll be stuck looking into facility insurance. At this point, lots of people also find they either can't afford to drive or it's not worth paying to drive.
The difference between these two offenses are pretty huge. This is what many here would call a "take it and run" offer.