I booked my 75 in for an MOT last week. So far it's never failed and I was pretty sure it would be ok this time too. The only worry I had was my rear tyres were pretty much down to the legal minimum, with money being a bit tight at the moment I thought I'd risk it and try and get a few more weeks out of them. One hour later I had a phone call informing me that my car had failed its MOT......because of the rear tyres! Anyway two new tyres later and I now have a new MOT. It's my fault I've ruined my cars perfect pass record, I shouldn't have risked it but the guy who did the MOT made me feel better when he pointed at a four year old Golf in the car park and told me it had failed with a list of faults longer than his arm. So all in all a ten year old car that only need two new tyres to pass its MOT isn't so bad after all!
I went through a very similar scenario 2 weeks ago. My rear tyres were right on the limit several weeks previously, I bought a new pair in when I had the money and didn't swap them out until the day before the MOT. They would definitely have been a fail. At 8 years old I got an advisory on a slightly rusted front N/S brake pipe.
Treated properly, these are bloody good cars.