Can I stop using Vive later if I change my mind?

Yes, you are not tied in. For goal-based investing and wealth management you can withdraw part or all of your capital at any time, or pause your contributions.

For a pension account fiscal rules apply: the money is locked until your retirement date. Withdrawing it as cash means repaying the deduction you received plus 20% revisierente. Transferring to another lijfrente provider is possible without fiscal consequences, via the PSK.