Any person who has a revenue that is subject to the payment of Swiss AVS / AHV 1st Pillar contributions is entitled to save with the 3rd Pillar, which could help to save on some taxes.
For independent workers the limit is set at 20% of their net earnings, but at the most 40% of the limit set by the 2nd Pillar contributions (cf. art. 7 al. 1 let b OPP 3), so this is currently CHF 34,128.
For anyone who is insured with the 2nd Pillar this will affect how much they can pay into the 3rd Pillar, and the limit is then currently set at CHF 6,826 per annum (cf. art. 7 al. 1 let a OPP 3), this being 8% of the upper limit of the 2nd Pillar contributions.