I just need a quick answer, I would like to know what is the best practice for coding an user page? Should i create 2 differents pages one for myself and one for other user's or only create one page, and modify the page programatically ( ex:if personnal page do this , else do that)?
A quick answer: from network/browser performance perspective it is better to create as consize pages as they could be. I.e. separate functionality (view-only/view-modify) should get a separate page since you would load different resources for each one and the functionality you don't need would affect the loading time (downloading, parsing, compiling, rendering).
Though it really depends on the environment of your website (network speed, user's device hardware) and size of your resources, since saving 5Kb between a view-only and a view-modify template would be an overkill.
So the best practice would be the following: understand your website requirements (page loading time, page navigation time), understand your website limitations (page size, network speed, user's device hardware), understand your time bounds (when your website need to go live) and basing on that choose your architecture.