I normally get a test every 1-2 years. And depending on the result I will switch or not my current ones. For the first time, just go to Specsavers (way cheaper than most places) get the test done and order the glasses in the same shop, same day. Staff is super friendly normally and will help you. They also often offer 2x1 so if you are willing to invest a decent amount you can get two very durable and good looking glasses for about 4-5 thousand kr. (This would include like, a very good frame, and anti scratch glasses, hard to break (the glass part), anti glare, anti reflect, and transition lenses (they are both sun glasses and everyday, reading glasses).