Risks of using XP

I've already expressed my opinion on the wisdom of continuing to use XP beyond its "best before" expiry date next April, particularly for sensitive purposes such as internet banking. It was directed at the average user.

However I respect that a lot of folks, by choice or necessity, are still going to be using XP beyond next April. Estimates range from 10-30% of  Windows users will still be using XP. And that represents a huge cohort potentially exposed to essentially zero day exploits thereafter. 

In estimating the absolute risks of continuing with XP/sp3, one can look back to what happened when MS discontinued support for  XP/sp2 in 2010. Over the next 2 years, infections of  XP/sp2 averaged 66% above those using XP/sp3.
http://www.techworld.com.au/article/530480/windows_xp_infection_rate_may_jump_66_after_patches_end_april/

In terms of absolute risk, users of  XP/sp3 averaged about 10 infections/1,000 computers, compared to about more than 16/1,000 for XP/sp2, between 2010 and 2012. These estimates are based on quarterly statistics. The cumulative risk over time is presumably higher. So regardless of which flavor of XP one currently uses, the average user faces about a 1-2% risk of infection per quarter at this time, when XP is still supported This risk might seem acceptable to many, who will choose to keep XP online. It will surely rise when support for all XP is dropped. Nobody can predict by how much.

I have seen several discussions in other security forums on how to "harden" XP so as to safely continue to use it after support expires. Most require a degree of expertise beyond that of the typical user (and certainly beyond mine). I remain skeptical.