In Finland, it simply is mandatory. Unlike in Sweden, there's two options:
- You're missing a hand, leg or both --> Physically inept for service.
- You're declared insane --> Mentally inept for service (and often, society in general).
If you still want nothing to do with the military, despite you're healthy mentally and physically, you can always do civil service, which is more than the double the length of regular military service. BUT, many companies and people higher up the management despise people who don't do their duty, and they won't hire you. People who do civil service are often labeled as "pus*ies" in Finland.
So, it was simple for me, i just joined the military and had, retrospectively, a quite fun time actually.