You can retire from your preservation fund any time after the age of 55. There might be certain tax implications when you do retire from your preservation fund that you would need to consider.
At retirement, for any non-vested benefits in a preservation fund, you are allowed to access up to 1/3rd of the funds in cash, subject to taxation, while the remaining portion must be used to purchase an income for life (Living annuity or guaranteed annuity) at retirement. If your fund value is less than R 247 500 when you retire you can access the full amount in cash, subject to taxation.
For any provident or provident preservation fund vested benefits at retirement, you can however take the full benefit as a lump sum, or take a portion of the benefit as a lump sum and purchase an annuity with the rest.