When to use ValueTask?

Despite having used C# for a while I'm... not that familiar with async. I know people sometimes say to sometimes use

ValueTask<T>

ValueTask<T>

instead of

Task<T>

Task<T>

, but when should you exactly do this? The extent of my knowledge (and reading the docs) is that

ValueTask<T>

ValueTask<T>

is like a DU between either a

value or a

Task<T>

Task<T>

, so is it ideal for situations in which an async method may just return a cached value?