The observational properties of Z Cam stars, nova-like variables and nova remnants are discussed in terms of the disc instability model. The effects of irradiation on the secondary star, giving rise to high and low states of mass transfer, and on the inner disc, suppressing or greatly reducing the disc instability, are used to explain the light curves of VY Sd stars. Irradiation may also play a part in producing low amplitude modulations in brightness of nova-likes on time scales of tens of days.