No you do not have to. ASDF knows where to find your ASD files:
https://asdf.common-lisp.dev/asdf.html#Configuring-ASDF-to-f...
Personally I use the (:tree (:home "dev/lisp")) form.
https://asdf.common-lisp.dev/asdf.html#Configuring-ASDF-to-f...
Personally I use the (:tree (:home "dev/lisp")) form.