It depends on how many keywords phrases people search into the search engines to seek out what your company provides and how many pages your site has. You can typically target anywhere from 2-5 keyword phrases on any one page of your website.
2-3 keyword phrases are good and select proper and long tail keyword. You can target 3-4 keyword in a web page.
I also agree 3 to 4 keyword phrase is good in use and if you use more than limitation then it will count in keyword stuffing.
Idea is good but now single keyword/phrase per web page is more beneficial to target because this reduce multi-targeting keyword/phrase confliction.
I am also suggest to you, 2-3 keyword phrases are good for target and 3-4 keyword phrases are good in a web page(inner-page) for targeted. Keep it up...
Well, on one page you should target 2 or 3 keywords for good result.
AS per my experience, You may target one primary and two would be secondary keywords. These are the best ratio so you can concentrate on all keywords.
You can target 3 keywords per page.