Accodring to official message from IELTS, there is no 90-day limit for test re-take from May 2006!

From 1 May 2006 the policy on candidates re-taking IELTS will be amended. The restriction on re-taking IELTS within 90 days will be removed and candidates will be able to repeat the test whenever they wish.

The current restriction on repeating the test within 90 days at any centre will remain in place for all candidates until the end of April 2006. All candidates from 1 May will be able to repeat at the next available test, regardless of the date of their previous test.