This lecture discusses the seismic assessment according to the Swiss Prestandard SIA 2018:2004, which later became SIA 269/8. It covers the seismic design specifications in SIA codes over the last 50 years, the compliance factor, and the acceptance criteria for risks to persons. The lecture also explains the concept of non-deterioration for seismic retrofitting, the efficiency of interventions, and the evaluation of risks to persons. Various case studies of seismic retrofitting in different types of buildings are presented, along with the cost implications. International ramifications of the Swiss approach to seismic assessment are also discussed.