Just do it!
Recently I decided to sell out old 2013 21" iMac. It had dust under the glass in front of the LCD screen in the lower right and left corners. I have read elsewhere this is not uncommon. Wanted the machine clean for sale.
The machine had AppleCare. Free screen replacement at local Apple Store in 24 hours. The bill without AppleCare was almost $500. So yeah, its worth it.
do you have to buy applecare in your own country? i am in canada, can i get the discounted B&H?
If you aren't reasonably close to an Apple Store or authorized repair center I'm not sure how you would get the machine back to Apple.
Here in Japan Apple sends a courier with a special shipping container and you just hand them the Mac. They overnight it to the service center in Tokyo and then overnight it back after repairs.
B&H will ship to Canada and even offers free shipping on orders over $99. I think you will need to call them about the Applecare though because their website shows discontinued.
I don't know if L.A. Computer will ship to Canada. You could ask them as well.
You do not need to buy AppleCare in Canada to use it there. I have registered AppleCare in Japan that I purchased at L.A. Computer in the past. I had it shipped to family members in the states who forwarded it to me.
AppleCare is highly recommended. B&H Photo mentioned above and LA Computer still sell the standard AppleCare plan (3 years extended warranty, no accidental damage) for a discount. You will need to call Apple directly to register it over the phone. I got the AppleCare for my 2017 iMac for even cheaper from a third party seller on Amazon.
I didn't opt for it on my mid- '11 and I've had no failures. Consumer Reports show Apple products as the most reliable. That was good enough for me.
I would be cautious with third party sellers, not saying completely avoid but just to be cautious. Applcecare fraud has been a big business in the past.