Generally speaking, deposts to and redemptions from your Vault are possible 24/7 unless you add a policy which dictates otherwise. Caveat: Trading heavily on Synthetix and other similarly designed exchanges may occasionally make redemptions not possible because of their delayed settlement design. The Guaranteed Redemption Policy ensures that your Vault has a policy which restricts you from trading for at a set, fixed time every day so that subscribers know with certainty that they can redeem within this window. This is a recommended policy to have if you will be trading with Synthetix. If you have any questions about using this policy, come and discuss them with us.
Note that in the screenshot, the Guaranteed Redemption Window configuration is toggled on for display purposes. If you do not plan on using this configuration, make sure they are toggled off.