An implantable spool is used for spooling the excess wiring associated with a lead that extends between at least one electrode and a pulse generator of an electrical stimulation implant system. The present invention also has application to providing a spool for coiling tubing of an implantable drug delivery system. Embodiments of the invention include a method of implanting an implantable system in a body, wherein the implantable system includes a source unit and an elongated member. A method of assembling an implantable system is also described.