The main purpose of this article is to analyze current status of companies' readiness factor for 4 th industrial revolution. Also, we wanted to present a maintenance model idea for a company implementing Industry 4.0. principles. Based on our previous research, firstly machinery maintenance as a phenomenon and its place in a production process is presented. Since every author defines machinery maintenance on its own, we try to choose one, which "fits" best for us. Various types of different approaches to maintenance (based on historical, socio-economic or production factors) are presented here. Also, a correlation between the industrial revolutions and machinery maintenance is shown. In the next part of the article various types of machinery maintenance (according to many different conditions) are presented. Also, based on the previous research there is an obvious correlation between the level of Maintenance and Industrial Revolutions presented. Main part of the article presents an ideal model proposition of maintenance in Industry 4.0. This is based on three main components: hardware, software, humans and organization. This also correlates with the previous research which was made.