Quick question about Minoxidil

I'll keep it really short..
Should minoxidil be applied only to the portion where there is hair loss or to the entire scalp?

In my case, I have hairloss only at my temples. Will it help applying minoxidil all over the scalp? Though I am aware Minoxidil might not work too well for temple region.

How old arer you? Do you have a strong family history of MPB (male pattern baldness)? Are you showing any beginning signs of hairloss in the crown?

I am 25 years old.. and have noticed recesion at temples a year back. Though I suspect I might be losing at a very slow pace at other areas too. Does minoxidil helps in the "overall hair strength", rather than the area of application alone?
I am using finasteride since a year and minoxidil only along the hairline. Pics posted here:
http://www.baldtruthtalk.com/showthread.php?t=3424
I have a history of MPB running in my family but I am really worried that I might bald much earlier than others in my family.

Minoxidil can only have effects in the area where it is applied. Because it is a vasodialator it does increase blood flow/circulation and may help to strengthen hairs that are weakening due to Male Pattern Baldness. However, it has been effective in some patients while on others dod not have any significant effects.