Questions, questions...

[Schlips1]

Originally Posted by raywright1

if the SIM is extended only according to the top up amount, it seems useless to keep a SIM since I cannot justify topping up and extending the card if I am not in the country to use it on the local network. for example, it would cost too much to keep topping up every 30 or 60 days from Nov 2010 until summer 2011. i would never be able to consume that much credit that i would accumulate.

Just top it up, when you want to use it! The money will not get lost during hybernation! In most cases it does not make sense to keep it active (for outgoing calls). But you may use it in hybernation (eg. in the USA) to receive SMS. Because they are free!

Originally Posted by raywright1

what is the behavior of the SIM between the 4-month validity and the 10-month (300-day) expiry date? it seems the least expensive way to keep a number in perpetuity is to wait until the 300-days is approaching, but by that time, the SIM cannot be used outbound unless it is topped up right? and in this case, the small top up amounts only get me a short extension.

Yes, that's it. But do not forget to top up!

Originally Posted by raywright1

i'm still not clear about the best strategic time to top up if i want the same phone number for the summer 2011: prior to Nov 11 2010 (top up while abroad), or July 2011 when i actually arrive on the local network? or is there another option: to invoke a billable event prior to nov 11 2010 and do not top up at all if i am content with my credit level?

I would do it while roaming before you are leaving. So you may use it when you 'll arrive (especially in a case of emergency).