But not everyone may pay in. There is a clear condition that must be met.
Tied private provision is intended as a complement to working life. That is why only people who earn an income subject to AHV contributions may pay in. Anyone who works and receives a salary or fee can build up their pillar 3a, employees as well as the self-employed. Anyone without earned income, however, for instance because they are not in gainful employment, cannot pay into pillar 3a. Pillar 3a is therefore deliberately tied to gainful employment, not to age alone and not to mere residence in Switzerland.
This link to earned income has a logical reason: pillar 3a is meant to take effect where income is earned and taxed, and to enable the tax-privileged build-up of private provision precisely there. Anyone in gainful employment should use this opportunity year after year, so that their retirement provision can be built up optimally.