I was convicted for drugs and firearms in Norway. The only time it has ever come up during my many years as a programmer, was when a consulting company I worked for had the police IT service as a candidate for my next project.
Since it was for the police, a background check would be required. I politely told my department head that I would not pass that, and a short summary of my case. At that time I had worked for about 2 years and got a kind "we would never have guessed" and "you will get another project then".
As a side note: In our country, an employer needs a legitimate reason to do a background check, and they won't see crimes that are not relevant, or for some crimes - too long ago.
Since it was for the police, a background check would be required. I politely told my department head that I would not pass that, and a short summary of my case. At that time I had worked for about 2 years and got a kind "we would never have guessed" and "you will get another project then".
As a side note: In our country, an employer needs a legitimate reason to do a background check, and they won't see crimes that are not relevant, or for some crimes - too long ago.