When to use IComparable<T> Vs. IComparer<T>

I'm trying to figure out which of these interfaces I need to implement. They both essentially do the same thing. When would I use one over the other?

Well they are not quite the same thing as IComparer<T> is implemented on a type that is capable of comparing two different objects while IComparable<T> is implemented on types that are able to compare themselves with other instances of the same type.

I tend to use IComparable<T> for times when I need to know how another instance relates to this instance. IComparer<T> is useful for sorting collections as the IComparer<T> stands outside of the comparison.

Use IComparable<T> when the class has an intrinsic comparison.

Use IComparer<T> when you want a comparison method other than the class' intrinsic comparison, if it has one.