Silver artefacts on open display are often protected from tarnishing using cellulose nitrate lacquers. Cleaning and relacquering is time consuming and has damaging long term effects over many repetitions. Hence optimization of the period between treatments is of great interest. The lacquer degrades over time, diminishing the protective effect and the effective lifetime is unknown. Aesthetic effects and the loss of reversibility can also affect the lifetime of the coating. Cellulose nitrate lacquered sterling silver coupons were used to replicate silver collections in museums, specifically the Portuguese Centrepiece at Apsley House. The effects of light and varying relative humidity (RH) levels on deterioration were studied using accelerated ageing. Fourier transform infrared (FTIR) analysis indicated cellulose nitrate lacquer is effective in protecting silver against tarnish after 20 years equivalent light ageing and at least 10 years equivalent ageing in low and mid RH environments. The lacquers remained soluble in acetone after the ageing regime.