Maintenance work can be divided into three primary categories:  mechanical, information technology and structural. Many people assume  that maintenance work relates solely to the ongoing repair of physical  components, but it can be used to describe any type of ongoing work or  effort required to maintain current operations. Although the work might  be in different environments, the people who are drawn to maintenance  work typically enjoy problem solving, facing challenges and using  analytical skills. 
Mechanical maintenance work is focused on  physical units or systems. In general, the term is applied to mechanical  systems, such as cars, heating or manufacturing machines. The level of  skill required varies widely, based on the type of system,  the primary purpose and the unique challenges created by the work  environment. For example, maintenance work on a car includes the  replacement of fluids that are used during the course of car operations.  Maintenance of a manufacturing machine might include replacement of key  parts that are worn away by extreme heat or the exposure to chemicals. 
Information  technology includes hardware and software components, both of which  require ongoing maintenance work. Hardware needs to be maintained on a  regular basis in two critical areas: operating system and physical components. The operating system  is the type of software used to control the equipment and support other  programs.
 The physical hardware unit includes electronic components,  fans, power sources and other items that might require repair or  replacement. Software programs are subject to maintenance work as well. Large  systems often have upgrades, patches or fixes that need to be applied to  keep them running properly. In addition to these minor, scheduled  maintenance tasks, all programs need to be maintained. This work  includes adjusting existing programs to suit new requirements and  fine-tuning programs to meet changing support structures. Software  development departments typically dedicate between 40 percent and 60  percent of staff time to software maintenance. 
  Structural maintenance work is performed on buildings, bridges and  other construction projects. In many cases, the asset is so large that  maintenance is an ongoing project that simply starts again once an  entire cycle has been completed. Roads, bridges, highways and traffic  systems are all subject to ongoing maintenance. These efforts are built  into the product lifespan, and without them, the entire infrastructure  would need to be replaced because of widespread failure. In many cases,  this work is scheduled in advance, to minimize disruption and to  coordinate with weather conditions in the area.