I genuinely feel safer that the vast majority of adult males in my country do know how to use an assault rifle, aim the rifle by using the sights and know how to clean it… or will remember after a 10 minute recap on the weapon. — ssu

Amen, and for that, universal conscription. Between the ages of 17 and 29 (for example), 8 months active service to include training and two years active reserve. All mandatory. Yes?

From the Finnish Constitution:

Section 127 - National defence obligation

Every Finnish citizen is obligated to participate or assist in national defence, as provided by an Act.

Basically all males between 18 and 60 years are in the reserve, meaning that they are liable to military service. Hence during wartime the government theoretically could force into the army even those that haven't done conscription, but opted for the non-military service. Officers and non-comissioned officers are up to 60 years in the reserve and the enlisted up to 40 years. Actual combat troops are below 30 years and only a minority, quarter of a million or so, have a position in the wartime army (from the basically 700 000 strong reserve). Career soldiers make about 2% of the wartime force. All this makes the wartime army quite old in age.

I remember just two weeks ago sitting in the canteen (soldiers home) during an excersize. There were British troops (Desert Rats) there eating pizza and waiting for helicopters to come to pick them up, which is a very rare sight in non-aligned Finland. One career officer commented: "Those British soldiers look so young." I had to comment "No, we are so damn old." It perhaps hadn't dawned that British professional soldiers are basically as young as our conscripts are. Youngsters indeed.

(Well, universal conscription works if you have a need for the deterrence. Otherwise, let's say if we would have a +1000 km border with Canada, we would have a tiny professional army that nobody cared about.)