It depends on the vitamin. Some vitamins, for example vitamin A, can be stored in your liver and therefore you don’t need a constant supply of it to maintain a healthy level in your circulation. There are several vitamins like this. For instance your body holds about 3 years worth of vitamin B12. Mice for example, are born with all the vitamin A that they need for their life times which they gain from their mother.
However certain vitamins are what we call water soluble, they cannot be stored by your body and must be used straight away. If you don’t keep a constant supply of for instance vitamin C ilnesses such as scurvy can occur.