When does it make sense to open a vested benefits account?

You are temporarily or permanently no longer employed (stay abroad, interruption of employment, further training, unemployment or childcare) and must transfer the pension fund assets to a vested benefits account
You have changed your employer and cannot transfer all of your previously accumulated vested benefits to the new pension fund
You become self-employed and do not join a pension fund
Your income is now – e.g. due to part-time work or a change of job – below the limit in the occupational pension plan (CHF 21’330; as of 2019)
As part of divorce proceedings, you are entitled to a part of your spouse’s pension assets