Riding hours per day, and per top end

I have read a couple of posts on here by people that say they sometimes ride up to 8-10 hours a day sometimes.

I have not got my bike working yet but when I do I would like to ride it about 3 times a week for a half day. I.e 3 mornings a week.

I only want to change my top end once a year so how much can i ride my bike per week whilst still only rebuilding it once a year.

I would like to ride about 12 hours a week sometimes more sometimes less.

Will this be ok, because some people say change your top end every damn five minutes and some people say once a year.

Opinions appreciated as I want to ride as much as possable but don't want to spend £300 every month.

Thanks

Its not a brit thing, its a student thing. I do not want to do it exactly every year but dont want to be doing all the time as this time it cost me nearly £300 to do including piston, bearing, gaskets, carb jets etc.

And I only work part time as im a full time IT student.