In quiescent phase of cell cycle, cells

Cells are of three categories base don the type of cell cycle they are in.

Type 1: Cells that undergo regular cell division follow the cell cycle as Interphase and M phase.

Type2: Some cells in the adult animals do not appear to exhibit division (e.g., heart cells) 

These cells that do not divide further exit G1 phase to enter an inactive stage called quiescent stage (G0 stage )

 Cells in this stage remain metabolically active but no longer proliferate.

Type 3: Many other cells divide only occasionally, as needed to replace cells that have been lost because of injury or cell death. 

These cells also do not divide further thus exit G1 phase and enter the inactive stage, quiescent stage (G0 stage )

Need to note that  cells in this stage no longer proliferate but remain metabolically active.

But  depending on the requirement of the organism these cells can come back to G1 phase and undergo cell division..