Duty and taxes at the border for paid services
 

I tried googling and searched RS with no luck.
Do you need to pay duty and taxes on services purchased in the country visited?

eg. You drive your car down to US and get your car painted, or getting dental work done, or breast implants, laser eye surgery etc.

Obviously these are things that are easy to "smuggle" across but just wanted to know the rules about it.

Taxes yes. If you were to get these things done in Canada, you would have to pay GST and maybe PST depending on what it is.
Duty, no. Duty only applies on items that is produced outside of North America, and labour does not count.

I only paid GST and PST on the labour, and duty on parts when I had my Koni shocks rebuilt by Koni USA.