Over here we just have every person registered in a central database from birth and it's mandated by law to keep the registry updated with your current address. The last census was in 2001 and then there was also done a big job registering every residences in multi residence houses. The assumption is that we will never have to do a form based census ever again and just use central registries instead.

That may or may not work depending on where you're at.

If for example you have poor compliance with the law then the law is mostly useless (in the US you do have to update your ID in 30 days, but huge numbers of people dont).

And that doesn't count if your country has a huge undocumented population, like some places in the US do.

That seems to assume that immigration and emigration is not a significant factor for your country

"Over there" is one of those countries where hundreds of people register their adress with the government at the house of an unsuspecting widow?

And how long does it take for that central registry to be informed when somebody has emigrated from the country without informing the government? Five years? Ten?