Hey Tom,
Charges are not directly linked to subscriptions, however they do have an `invoice` attribute[1], and invoices have a `subscription` attribute[2].
When retrieving a charge[3], you can use the expanding feature[4] to directly expand the `invoice` attribute into a full invoice object so you don't have to retrieve it separately.
If you want to retrieve all charges for a given subscription, you can do so by listing all invoices[5] with the `subscription` parameter[6]. Each invoice has a `charge` attribute[7] that you can use to retrieve the charge for that invoice.
You can use the expanding feature there too, by including `data.charge` in the expand list so that the charge objects are directly expanded in the list of invoice objects that is returned by the API.
Hope this helps!
Best,
Olivier