When I was at school we were taught that numbers were fine, upstanding, honest things. When you added two to three the answer was always five – whether you did two plus three or three plus two it was always five. You could even do it in reverse and take away three from five and get two. And it worked every time. You could do it with apples or oranges, bananas or pears – although, of course you could not add apples and pears unless it was time for bed.

But now I don’t trust numbers so much. Why is it that I can get into a size 10 in one shop but need a 12 in another? Surely 10 is 10 and 12 is 12. And then we hear that the current Marks and Spencers size 10 is the equivalent of the 12 of a few years ago. So what is it?

And when numbers relate to time it is even worse. My doubts started when I was a child. The six weeks summer holiday lasted five minutes and Christmas Eve was never, ever only 24 hours long – whatever anyone tells you. It is no better today. A five minute job takes 20. The 20 minute trip to work lasts an hour and my husband’s hour in the pub lasts an evening.

And as for age! When I was eight I was very specific. I was eight years and four months. By the time I got to fourteen I was ‘nearly 16’ and when I finally got to 16 I was most definitely 18. Now I am in my mid-twenties (29) I have a lot of friends in their thirties – some of whom have been there for 18 years to my knowledge. There was some interesting research done for Liverpool Victoria that showed that three quarters of 50 year olds only felt 75% of their age.

So 50 is the new 40. A few years back we were told we would all retire by 62 at the latest and preferably before that this would be ‘good for the country’. Today, apparently, it would be good for the country if we all worked until we are 70. We also must plan for our future but of course that could be when we are 60, 70 or 80 when our bodies will look 40,50 or 60 but we will act like we are 30, 40 or 50 and expect to live for another 10, 20 or 30 years. And I thought Doctor Who was the only Time Lord! Lucky Doctor – he has his Tardis to live in. No mortgage on that I bet. If there was I don’t suppose it was over a 25 year term. 25 thousand more like! Yet when you applied for your first mortgage you were probably told you had to pay it back in 25 years. If the average first time buyer is 25 then I wonder how many 50 year olds own their home with no mortgage. It is more likely that the term has been extended and extended following house moves and the odd home improvement additional borrowing to pay for the conservatory, decking or enhance the driveway by putting a new car on it.

When you finish paying off your mortgage how will you blow all that extra cash every month? Before you start looking at the holiday brochures cast an eye over the income you will need in retirement (at least £12,000 a year apparently) then look at how much your existing pension arrangements will give you. So I should start putting that spare money in a pension pot – and even then it may not be enough. If it is not then you may need to consider resurrecting your friendship with your local building society. The advent of the ‘lifetime mortgage’ suggests that people in their silver or golden years (I have lost all trust in numbers now) may need to use their home as capital to provide them with an income later in life. Instead of you paying your lender every month your lender pays you!

I must make a very serious point here. This is a big step to take and it will mean that your children will not inherit the full value of your house – so it is not something that should be done lightly.

So perhaps you should ask your lender if they will still love you when you are old and grey.

Will they still need you; will they still feed you, when you’re 64?