Disability aids are often mobility aids. These are devices designed to assist walking or otherwise improve the mobility of people with a mobility impairment. There are various walking aids which can help with impaired ability to walk and wheelchairs or mobility scooters for more severe disability or longer journeys which would otherwise be undertaken on foot. For people who are blind or visually impaired the white cane and guide dog have a long history of use. Other aids can help with mobility or transfer within a building or where there are changes of level. Traditionally the phrase \"mobility aid\" has applied mainly to low technology mechanical devices. The term also appears in government documents, for example dealing with tax concessions of various kinds. It refers to those devices whose use enables a freedom of movement similar to that of unassisted walking or standing up from a chair. Technical advances can will increase the scope of these devices considirably. Edinburgh Volunteers can work through the Edinburgh Voluntary Oganisations Council which had a \"Volunteer Job Shop\" to help people interested in volunteering find opportunities. This was one of the very first in the UK. After forty years that little project has evolved from \"Job Shop\" via \"Volunteer Exchange\" and is today Volunteer Centre Edinburgh (VCE), an independant company since 2000 and today employing 24 people and engaging 90 volunteers. Over the years VCE has always been at the vanguard of the development of services to volunteers. Edinburgh volunteers works to ensure that every volunteer involving organisation offers an excellent volunteering experience. They inspire the development of volunteering opportunites in voluntary organisations, in the public sector and at grass roots in communities. This helps to match volunteers with jobs and opportunities suited to their abilities and history. A network of helpers are often called volunteers. In general terms, volunteering is the practice of people working on behalf of others or a particular cause without payment for their time and services. Volunteering is generally considered an altruistic activity, intended to promote good or improve human quality of life, but people also volunteer for their own skill development, to meet others, to make contacts for possible employment, to have fun, and a variety of other reasons that could be considered self-serving. Volunteering takes many forms and is performed by a wide range of people. Many volunteers are specifically trained in the areas they work in, such as medicine, education, or emergency rescue. Other volunteers serve on an as-needed basis, such as in response to a natural disaster or for a beach-cleanup. In a military context, a volunteer army is an army whose soldiers chose to enter service, as opposed to having been conscripted. Such volunteers do not work for free.