For a website a domain name and webhosting are essential. However, many times, the webmaster may have to change the domain registrar and webhosting for a number of reasons which may vary. In some case, the new webhost will offer better pricing and tech support, in other cases, the webhosting company will go out of business. In such cases, if the website is down, the webmaster should move their website or blog immediately to a better webhosting company, reduce downtime, and ensure that there are no loss of revenues.
There are 3 main reasons for changing webhosting 1. Planned change in webhosting because of financial or technical or ethical reasons 2. Forced change - when the webhosting company goes out of business and the hosting company does not offer any support. In some cases, they may give a prior warning 3. Temporary change for testing or troubleshooting the problems especially related to wordpress or mysql databases