SEO and Changing the host

Hi,
Does changing the host too frequently affect the ranking of the web site in search engines.
For example, if i change the hosting company 3 times in 2 months, does it affect the Page Rank? Because it is changing the server location, and also, each time the website cannot be accessed a few hours.

chances are there may be a slight drop depending on downtime but this really depends on what web site your running. If your getting lots of traffic i don't see too much of a loss really, really long term if you stay still.