The underlying principle is easy enough: a country grants the right to live there to non-citizens who commit a minimum sum in local eriseira real estate estate. The minimum investment is set very differently across programmes, and legislators revise it with limited notice.
One key point divides a residence permit and naturalisation. The permit lets you live in the country, typically on a renewable basis, whereas citizenship normally requires years of actual residence. A promise of nationality in return for an apartment purchase is reason for caution.
Past the headline threshold, such permits impose further conditions. Frequent requirements involve a clean criminal record, private health insurance, documented income and a minimum number of days on local soil annually. Overlooking a single condition can jeopardise the permit regardless of the kestel property prices.
Fiscal residency remains a separate question entirely. Having residency does not by itself make you taxable on worldwide income, and crossing the day-count threshold frequently does. Many countries use a day-count rule, and the effects touch foreign income.
The practical advice remains the same everywhere: buy something you would be happy to own, living in italy and treat the permit as a bonus. These routes close from time to time, and an apartment bought only for paperwork can be hard to rent and chlorakas rentals hard to resell.