JR Pass...how many days?

Another question regarding JR pass...

I'm going for 21 days, will probably spend 10 initially in Tokyo with day trips to Nikko, Kamakura, Hakone, Yokohama. Then we plan on going to maybe Takayama, Osaka, Kyoto, Hiroshima via Shinkansen & regular trains before returning to Tokyo for maybe 2 days at the end.

We also wanted to make day trips while staying in Osaka.

So...
Should we get a 14 day pass as we are initially staying in the Tokyo region? Or should I get 21 day pass so that it covers the Tokyo day trips?
Will the JR Pass cover these day trips anyway?
Will it cover Takayama as well?

Thank you in advance!

you can use a JR day pass to go around Tokyo by the Yamanote line and others but it doesn't pay unless you take the train for a short distance many times an one day. JR passes are meant to be used on long distance trips. A 7 days pass is only worth it if you go from Tokyo to Osaka and back (or any return trip about at least 3 hrs long one way). A 14 days pass is only good if you go much farther and all over the place. Check the price of all the trips you plan to do on WWW.hyperdia.com. Within Tokyo a prepaid smart card like Suica is best, especially if you buy a Suica/Nex combination to travel from Narita airport to downtown Tokyo or ..

Thanks for your advice and the web-link.

So for trips to Hakone, Nikko etc, I'd be better off buying individual tickets? I'm concerned it will ad up to the same amount anyway, because I've got quite a few day trips there...

There are many special passes sold to Nikko and Hakone, even if you add both a trip from Tokyo to Hakone and Nikko, it doesn't justify even a 7 day JR pass.

John is right. Last time I visited the Kansai for over 7 days I went all over the area with daily return tickets and altogether they were cheaper per day, than daily passes, never mind a 7 days JR pass.