An insertion system, the insertion system comprising: a base adapted to be carried by a patient; a first device housing configured to be operatively engaged with and disengaged from the base, the first device housing comprising: a first carrier body arranged for movement within at least a portion of the first device housing at least between a retracted position and an advanced position, the first carrier body for supporting a piercing member in a position orientated for insertion through skin of the patient upon movement of the first carrier body from the retracted position to the advanced position; a second device housing (291, 391) configured to be operatively engaged with and disengaged from the first device housing, the second device housing comprising; a second carrier body (298, 398) arranged for movement within at least a portion of the second device housing (291, 391) at least between a retracted position and an advanced position, the second carrier body (298, 398) operatively connectable with the first carrier body; and a driver (293, 393) arranged within the second device housing (291, 391) to move the second carrier body from the retracted position toward the advanced position to move the first carrier body from the retracted position toward the advanced position to insert at least a portion of the piercing member through skin of the patient; characterised in that the first carrier body has a structure which disengages the first device housing from the base upon the first carrier body being moved to the advanced position. a base adapted to be carried by a patient; a first device housing configured to be operatively engaged with and disengaged from the base, the first device housing comprising: a first carrier body arranged for movement within at least a portion of the first device housing at least between a retracted position and an advanced position, the first carrier body for supporting a piercing member in a position orientated for insertion through skin of the patient upon movement of the first carrier body from the retracted position to the advanced position; a second device housing (291, 391) configured to be operatively engaged with and disengaged from the first device housing, the second device housing comprising; a second carrier body (298, 398) arranged for movement within at least a portion of the second device housing (291, 391) at least between a retracted position and an advanced position, the second carrier body (298, 398) operatively connectable with the first carrier body; and a driver (293, 393) arranged within the second device housing (291, 391) to move the second carrier body from the retracted position toward the advanced position to move the first carrier body from the retracted position toward the advanced position to insert at least a portion of the piercing member through skin of the patient; characterised in that the first carrier body has a structure which disengages the first device housing from the base upon the first carrier body being moved to the advanced position. a first carrier body arranged for movement within at least a portion of the first device housing at least between a retracted position and an advanced position, the first carrier body for supporting a piercing member in a position orientated for insertion through skin of the patient upon movement of the first carrier body from the retracted position to the advanced position; a second device housing (291, 391) configured to be operatively engaged with and disengaged from the first device housing, the second device housing comprising; a second carrier body (298, 398) arranged for movement within at least a portion of the second device housing (291, 391) at least between a retracted position and an advanced position, the second carrier body (298, 398) operatively connectable with the first carrier body; and a driver (293, 393) arranged within the second device housing (291, 391) to move the second carrier body from the retracted position toward the advanced position to move the first carrier body from the retracted position toward the advanced position to insert at least a portion of the piercing member through skin of the patient; characterised in that the first carrier body has a structure which disengages the first device housing from the base upon the first carrier body being moved to the advanced position.