How quickly can I expect to see results?
That depends on what we're doing?
A simple one page Wonder of WordPress website can be 'up and running' in a very short time indeed.
But the creation of the site basics is only part of the work. There is a lof of behind the scenes work that needs to be done properly before the search engines understand what your site is about. Then there's getting the links from other sites, to help improve your page rank.
And if you're blogging, then you have to create the content.
Some work - such as simple configuration of plugin or module parameters can be done very quickly. Other stuff, such as advanced theming or complicated definition of Newsletters, Google Ads or simlar can take longer.
And then there's testing and the inevitable problem determination. Remember, that we are dependent on the rest of the Open Source community for developing quality solutions which we engineer to satisfy your needs.