It really depends on all round attitude. When I was there, some people failed countless times and were allowed to stay on the merits of their attitude and commitment. One person was discharged after failing his 3rd kit muster but was widely regarded as a dick.
The recruits here at Raleigh carry out at least three kit musters during their ten weeks but only have to pass their final one. They will get either three or four attempts at this final muster depending on how they have performed in their previous attempts.
It is a problem a lot our modern day youngsters have, the modern day dress sense of un-kept, un Ironed (Or Not Ironed by themselves?) has led to a generation that do not know how to Wash and Iron cloths, if he has some shore leave and can come home? Give him a pile of ironing to do the kit must standard, he will be well pissed Off but may help him or at least give you a rest from ironing?
Kit inspections are a good way for a team of Newbies to gel together, recognising each other's strengths and weaknesses. They will find some recruits are good at bulling boots, ironing creases, sewing, etc., so if they help each other out it will make life easier in the future. Additionally, the Instructors themselves should be consulted for advice if they are struggling; I am sure the CPO/PO would much rather a recruit approach them to ask a simple question now rather than bottle it up and fail at a particular task in the future, thus wasting all the time and effort invested previously to get to that point in their basic training.