Hola,
I've noticed in this construction that desde is used at the end of the sentences, and within the middle of the construction it is not.
Trying to extend my learning with the following example
Llevaba cinco años sin fumar.
Could you say
Llevaba sin fumar desde 2015
Llevaba sin fumar desde hace cinco años
?
I'm thinking in terms of the construction when there is a specific date in mind (2015), compared to the 'ongoing' desde hace without a specific date.
Gracias,