My passport runs out in February 09, when should I renew it? I will not be using it until October 08 for about two weeks and then not again until after Feb 09.
Depends where you are going in October. A few countries (and far far fewer than people would have you believe) have a 3 or 6 month validity requirement. If you are going to one of the latter renew now.
Renewing now is a good idea anyway - you will avoid any possible fees increases between now and the time you renew it and the renewed passport will still expire in February 2019 - you get the unused time creditted.
Although you can have a maximum of 9 months unexpired validity credited to a renewed passport and this makes renewing early a good idea, bear in mind that last week's 3-day strike by passport workers has caused a backlog of applications. The timescale to clear the build up is estimated at up to one month.